CORROSION Behavior of AL-Mn ALLOY Dissertation Assignment

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CORROSION BEHAVIOR OF AL-Mn ALLOY

Abstract

Aluminium alloys are widely used in the fields of electric module packaging, electronic technology, automotive body structure, wind and solar energy management, due to the advantages of high specific strength, high processability, predominantly anti-erosion, increased conductivity, eco-friendly nature. The seamless Aluminum Manganese Tubing has a variety of dimensions including round, rectangular, square, and Round Aluminum Manganese Tubesoval in Rectangular Aluminum Manganese Tubesnumerous standard diameters from 0.02 to 6.0 inches and wall thicknesses from 0.003 to 0.500 inches. Tubing can be further processed to produce rings, washers, sleeves and sheaths. Tubes can also be produced from custom alloys for commercial and research applications and for new proprietary technologies. Other available shapes include bar or plate form, as well as custom machined shapes and through other processes such as nanoparticles and in the form of solutions and organometallics.

Computational Fluid Dynamics (CFD) modeling was used and this work was performed in the software ANSYS FLUENT. A numerical three dimensional (3D) symmetric model was built to simulate the corrosion procedure with the assumption that the inert material water is flowing inside the pipe. The realizable k − ε turbulence model was used to model the effects of the turbulence.

Several simulations with different inlet mass flow rate, different inlet temperature and different inlet diameter was calculated to see the influence of corrosion on the pipe. Then, the whole pipe system was modeled with particle injection. The Discrete Phase Model (DPM) was used to simulate the particle motion in the pipe and the focus was on the influence of the corrosion level. Finally, the suitable corrosion at various velocity and diameter of pipe has been was calculated.

Keywords: Numerical modeling, Aluminum -Manganesse Alloy, corrosion process,

Discrete phase model, Ansys Fluent.

Table of Contents


Introduction 5

Background and Rationale 7

Statement of Problem 9

Research Question 10

Research Aims 10

Research Objectives 10

Initial Literature Review 10

Concept of Corrosion and Alloy 10

Properties of Manganese as Alloying Agent 15

The effect of Mn on the mechanical behavior of Al alloys 36

Charpy V-Notch Test 39

Impact test results on low- and high-strength materials 40

Theory 41

VOF Method 41

Turbulence Model 41

Corrosion Model 42

Discrete Phase Model 42

Project Philosophy 43

Interpretivism 43

Research Methodology 43

Data Collection 44

Secondary Research 44

Research Ethics 44

Material and Methods 45

Numerical Assumptions 45

Material 45

Geometry 46

Mesh 47

Numerical Models 49

Boundary Conditions 51

Inlet Boundary 51

Outlet Boundary 52

Inner Wall Boundary 52

Outer Wall Boundary 52

Methods of Solutions 52

Solution Initialization 52

Result and Discussion 53

Different Mass Flow rate 57

Different Diameter of the tubing 57

Conclusion 58

Future Work 60

Reference List 60

List of Figures

Figure 1 The Pourbaix Diagram for aluminum and water illustrates the stable phases for the different potentials and pHs. . 18

Figure 2 The dissolution-precipitation mechanism of aluminum corrosion 19

Figure 3 The surface of aluminum after one day in hot water (62’C.) (B) Schematic of the multilayered hyroxides film on aluminum 20

Figure 4 Exfoliation of alloy 7075-T6 after six years seacoast exposure in the bare con- dition. 24

Figure 5 corrosion rate as a function of Mn vs. AL presented from weight loss data 40

Figure 6 Material Properties of Al-Mn Alloy tubing 47

Figure 7 Al-Mn Alloy Tube geometry 48

Figure 8 Body sizing Mesh 49

Figure 9 Inflation Mesh Details 49

Figure 10 Meshing of the tubing 50

Figure 11 Viscous Model 50

Figure 12 Discrete Phase Model 51

Figure 13 Set Injection Properties 52

Figure 14 DPM erosion rate 55

Figure 15 DPM concentration 56

Figure 16 Static Pressure 56

Figure 17 DPM accretion rate 57

Figure 18 Plot Particle Residence Time vs Time 57

List of Tables

Table 1 Corrosion rate data for the various Al-Mn alloy in 0.25 M HCl concentrations 14

Table 2 Corrosion rate data for the various Al-Mn alloy in 0.5 M HCl concentrations 14

Table 3 Corrosion rate data for the various Al-Mn alloy in 1.0 M HCl concentrations 15

Introduction

Aluminum alloys are of interest for various applications, particularly due to their high strength/weight ratio, good formability, good corrosion resistance and recyclability potential in vehicles, household items, infrastructures, constructions, aerospace, etc. In Al alloys, Si, Fe, Mn, Cr, Cu and Mg are introduced at various levels, mainly to improve the mechanical strength. Si and Fe are normally present as unavoidable impurities in commercially pure Al up to a total of 0.5 wt%, but may also be introduced at higher levels. During the manufacturing process stages, these elemental additives may create various kinds of insoluble intermetallic particles (IMPs) in the alloys and, to a lesser extent, precipitate from soluble alloying compounds and influence the final product properties (Vargel,2000).

It has been calculated that for each kilogram of weight saved in a vehicle, a saving of ca 20 Kg of CO2 emissions can be achieved. Therefore the use of aluminum in the automotive industry in order to produce more fuel-efficient vehicles and to reduce the energy consumption and air pollutions has increased greatly over the last few decades, from 20 Kg in 1960 to a predicted level of more than 160 Kg per vehicle in 2010 (Gray,2005) and 250 to 340 Kg by 2015(Miller,2000). One of the increasing applications of Al alloys in vehicles is in heat exchangers (with tube and fin components) such as radiators, evaporators, engine cooling and air conditioning systems. In the past, aluminum heat exchangers were assembled mechanically, but nowadays tubes and fins are joined together by a brazing process using a brazing Al-Si alloy layer that has a lower eutectic temperature than the tube or fin core alloy. The rolling production line and details of brazed heat exchanger components including tube, fin and brazed layer made from braze clad Al-Mn alloy EN AW-3003 in Sapa Heat Transfer. During the past fifteen years the standard commercial Al alloy for heat exchanger applications is the EN AW-3003 (AA3003) Al alloy containing about 1 wt. % Mn. This grade of Al alloy has good formability, mechanical strength and acceptable corrosion performance. In addition, developing alloys based on the EN AW-3003 composition has improved the corrosion.resistance, especially that of tube alloys, so called “long-life” alloys. Figure 1.2 represents the trend of the reduction in thickness of tube and fin materials in automotive heat exchanger applications during the last few decades. For alloys used as fins, the longterm mechanical and corrosion performance is of increasing importance, particularly as down-gauging of strip continues, to 70 μm thickness and even less in the future (Miller,2005).

When required, i.e., during exposure to a corrosive environment, the fin material should act as an efficient sacrificial anode to protect the tube from being perforated, as shown in Fig. 1. In addition, the fin material should have high intrinsic corrosion resistance to maintain the material integrity and the mechanical properties in long term service. Therefore, designing and developing new tube and fin alloys with improved corrosion properties in both water-side (internal) and air-side (external) situations require a detailed understanding of the corrosion mechanisms of these alloys (Gray and Miller, 2005).

It is to be noted that Corrosion behavior of alloys and metals are mainly affected through their environment. In the open atmosphere, corrosion gets depended on the variations of seasonal weather. Now, these atmospheric environments can be segregated as; urban, rural, industrial and marine. It is evidence that corrosion behavior of the metallic materials are being used in the biomedical applications which is of high significance of biocompatibility. It is very true that corrosion behavior of alloys and metals are considered to be very similar within the human body as within other aqueous solution along with corresponding of electrolyte composition. Now, this research focuses on studying the corrosion behavior of aluminum and manganese alloy.

The role of manganese in the corrosion behavior of commercial Al-Mn alloys has been examined by means of corrosion tests and metallographic techniques. Alloys containing 0.4–1.2% Mn, 0.4–0.8% Fe, 0.15% Si and some with small amounts of magnesium have been fabricated and evaluated. Results have shown that corrosion resistance increases with an increase in the Mn/Fe ratio in the alloy, but remains unaffected by the magnesium addition. The beneficial role of manganese is interpreted as reducing the difference in potential between the matrix and the intermetallics because of the supersaturation of manganese in the aluminum matrix and the manganese enrichment of the intermetallics. This reduction in the potential difference between the matrix and the intermetallics decreases the extent of overall corrosion. (M Zamin, 1981)

Typical levels are around 0.5% Mn for solid state grain growth control in the medium and high strength alloy range, and extend to 1.3% Mn for strengthening pure aluminium.

Background and Rationale

Manganese is being known to be the alloying element of the Al alloys which contributes up uniform deformation. In the current times, it has been found that the manganese possess with increase nearly over 0.5wt% in such the aluminum alloys seem to have 6000 and 7000 series of alloys (Nam et al. 2020). Now, both these involved in yielding potential tensile strength which increases in significant way without reducing up the ductility. Now, this added manganese does form a dispersion which is known to be; Al6Mn (Nam et al. 2020). The research has found that this dispersion possess with incoherent structural relationship regards to matrix (Nam et al. 2020). The observation of TEM has already proven that the corrosion behaviour of dislocation through analysing up the characters of dislocations away and around from dispersion. Now, different study has shown that adding of aluminium and manganese involved in increasing up tensile strength and importantly improves up low-cycle fatigue of resistance.

Aluminum is a very active metal, but it naturally creates a passive layer (Vargel, 2004), and its corrosion resistance depends on the passivity produced by this protective oxide layer. In the pH range of 4-9, the amorphous protective oxide (with an external side of bayerite, Al2O3.3H2O hydroxide gel) layer is formed in water or atmosphere with 2 to 4 nanometers thickness. The dissolution potential of aluminum in most aqueous media is in the order of -500 mV with respect to hydrogen electrode, while its standard electrode potential is -1660 mV with respect to hydrogen electrode. Because of this highly electronegative potential, aluminum is one of the easiest metals to oxidize. However, due to the presence of the naturally passive layer, aluminum behaves as a very stable metal, especially in oxidizing media such as air and water (Vargel,2004). The few existing defects in the protective oxide layer, which are inevitable even for the purest aluminum alloys, will cause the corrosion initiation. In the alloyed aluminum, the second phases are either cathodic or anodic compared to the aluminum matrix, and they give rise to galvanic cell formation because of the potential difference between them. Chloride-containing solutions are the most harmful ones as regards localized corrosion of aluminum alloys. Although pitting is the most common form of aluminum corrosion (Shreir,1994), in practice, different localized corrosion attack morphologies have been observed on aluminum alloys in different solutions (Frankel,1998). For pure Al with a crystallized structure, pitting develops along closely packed (100) planes, resulting in crystallographic corrosion (Sinyavskii, 2001).

Alloying generally leads to the initiation and development of pits formation that is less sensitive to the microstructure of the alloy matrix, but more related to the secondary phases. Corrosion of low-alloyed Al alloys is slightly localized along grain boundaries. A further increase in the content of alloying elements enhances the localization of pitting, as the amount of IMPs grows substantially. High-alloyed Al alloys are often susceptible to intergranular corrosion (IGC). One reason is that, in this case, the structure of the grain boundaries becomes more complicated due to the appearance of precipitates, the zones depleted of alloying elements, and the zones enriched in certain alloying elements and dislocation piles.(Sinyavskii, 2001) Tunnel-like pitting and narrow long channels have been observed on some commercial Al alloys, due to microstructure, solution composition, electrode potential and temperature. The reason for this behavior was discussed in terms of coupling of dissolution and mass transport (NewMan, 1995).

Statement of Problem

It is to be noted that Manganese being used for the alloying element for various different applications. Manganese is considered to be key component of steel. Now, effect of manganese in increasing and developing up the mechanical properties of steel eventually depends on the carbon content (AZO Materials, 2021). Several studies have already shown that when manganese gets added to the aluminum, then the strength gets increased slightly by the solution strengthening and also hardening of strain also gets potentially developed (AZO Materials, 2021). Now, the several studies have shown up overall corrosion behavior process gone through when both these two elements get merged. On the other hand, several studies have shown the experimentation process in the linear or sequential way mainly the briquetting process with aluminum slot and adding powder with electrolytic manganese gets mixed up to 2% of the total aluminum (AZO Materials, 2021). However, different studies have not shown the after effect of the conversion of these elements into alloys. Specifically, their use in the biological environment, the way actually works, their usage approach. Furthermore, several studies only focused on the strength rather than not going through the critical analyzing after the preparation of this alloy. In this context. The above mentioned is the problem statement which has been founded by the researcher. This research is going to shed light on the corrosion behavior process of both these two elements in alloys. In this context, the researcher will be focusing on areas where corrosion behavior of these two elements when becoming alloy in their approach.

Research Question

What is the corrosion behavior of al-mn alloy?

Research Aims

To investigate the corrosion behaviour of al-mn alloy

Research Objectives

  • To understand the material composition and structure of aluminium- manganese alloy
  • To determine the mechanical testing approach of aluminium- manganese alloy
  • To investigate the effect of Mn on the mechanical behaviour of the Al Alloys
  • To find the corrosion in the pipe by DPM

Initial Literature Review

Concept of Corrosion and Alloy

Corrosion

Corrosion occurs when the refined metal gets naturally converted into the more stable form such as; hydroxide, oxide or sulphide stating this leads towards the deterioration of material. This corrosion mainly caused when the metal corrodes and gets react with another substance like; hydrogen, oxygen, electricity or even the bacteria and dirt (TWI, 2021). This corrosion can also take place when the metals are being placed under too much of pressure resulting into the cracking of materials (TWI, 2021). It is to be noted that annually in the worldwide, the cost of this metallic corrosion is estimated to be nearly of $ 2 trillion (TWI, 2021). On the other hand, experts do believe that neatly of 25-30% can be prevented along with potential and correct corrosion protection (TWI, 2021). It is to be noted that poorly planned construction projects can lead towards the corroded framework which needs to be replaced considering it to be the waste of natural resources as well as contradictory towards the global concerns over sustainability.

Corrosion is derived from the Latin word corrodere meaning gnaw away which occurs as a consequence of a physiochemical interaction between the material, mostly a metal and its environment (Ekuma, 2006). Recognizing that many variables are involved, including environmental, electrochemical and metallurgical aspects may better give us an insight into the intricacy of the corrosion process. For example, anodic reactions and rate of oxidation, cathodic reaction and rate of reduction, corrosion inhibition, polarization or retardation; passivity, effect of oxidizers, effect of velocity, temperature, corrosive concentration, galvanic coupling and metallurgical structure all influence the type and rate of the corrosion process (Idenyi et al., 2006). Also, the statistical nature of corrosion governed by a number of variables can take different forms due to the varied forms of corrosion. For example; microscopic variations in a surface tend to cause different forms of corrosion and also variations in the corrosion rate over a pit area. This has hindered the full elucidation of the mechanism of this undesirable process and subsequently the determination of the necessary preventive techniques (Idenyi et al., 2006).

Metallic corrosion occurs basically as a consequence of their temporal existence in excited state; a refined state due to the absorbed energy during extraction from their ores. This makes them unstable and certain environments provides the possibility for these metals (or alloys) to combine chemically with elements in their environment to form compounds and return to their natural stable form of ground state known as ores with accompanying reduction in the free energy of the system (Ekuma and Idenyi, 2006).

The rate of corrosion attack can usually be estimated from relatively simple laboratory test in which small specimens of the related materials are exposed to a well-stimulated actual environment with frequent weight change and dimensional measurements carefully taken. The Corrosion Penetration Rate (CPR) usually expressed in mm/year is an important corrosion-monitoring parameter; as it provides corrosion engineers and scientists with reliable information on the service life of materials in environments and may be computed as:

where R is the rate of corrosion penetration mm/year, W is the weight loss in milligrams; A is the exposed specific area of the specimen in square cm, ρ is the density of the specimen in grams per cubic centimeter and t is the exposed time in hours (Ekuma and Idenyi, 2006). The use of this corrosion rate expression in predicting corrosion penetration in actual service is usually successful if the environment has been properly stimulated in the laboratory (Shreir, 1994) and the corrosion form uniform otherwise it becomes somewhat unpredictable with local disturbances (Idenyi et al., 2006).

The physio-chemical properties of materials are adversely affected by alloying elements, which its somewhat deleterious role in terms of corrosion resistance is diverse and well understood. Though, the alloying element generally improves the mechanical strength of the aluminium alloy, it however diminishes its resistance to corrosion. This is attributed to the highly thermodynamically unstable nature of the compounds formed by these elements that normally settle along the grain boundaries (Ekuma, 2006). This instability predominant in the grain sites is no doubt a good breathing zone for corrosion attack when the material is exposed to corrosive environments. Corrosion experts have attributed cases of intergranular corrosion to this phenomenon (Schweitzer, 1989). The corrosion resistance of aluminium is hampered by the presence of most alloying elements. For instance, elements like zinc, copper, magnesium, manganese, silicon, tin, copper etc, have been attributed to be the cause of most observed corrosion cases in aluminium alloys due to the formation of eutectic compounds. These compounds, which usually exist as phases, create galvanic cells within the matrix, causing flaws on the surface of the alloy, there by creating pits and intergranular cracking (Fontana, 1986).

At investigating the service performance of Al-Mn alloys in varying acidic concentrations. The outcome of the study is expected to be of great importance in material selection in corrosion design for aqueous acidic environments.

After the calculation for each of the Al-Mn alloy compositions have been carefully worked out and charged into a surface crucible furnace, the molten alloys were cast into rods after melt down, machined to sizeable dimensions and subsequently, cut into coupon samples of dimension range of 18×16.95×4.37 mm and initial surface area of about 1333.29 mm2. Each sample coupon was drilled with a 5 mm drill bit to provide holes for the suspension of the strings for immersion. The surface of each of the test sample was thoroughly polished with emery clothes of 500, 1000 and 1200 m grades as to remove any oxide layers, carbonized layer and any initial treatment(s) given to the Al-Mn alloys as to expose its structure for immersion. The samples for Al-1.5% Mn alloy were coded A, Al-2.5% Mn alloy were coded B and that for Al-3.5% Mn alloy were coded C. The initial weight of each of the sample coupon was carefully determined using a highly sensitive digital analytic chemical weighing machine.

The environments for this work were acidic environments made from stock solution of hydrochloric acid (HCl) with three different concentrations using normal procedure. The concentrations were 0.25, 0.5 and 1.0 M of the acidic solutions. All corrosion tests were carried out at room temperature.

Constant Immersion Testing

The specimen were polished in a progressively finer grade of emery paper up to 2400 grade with all the test coupons initially cleaned according to ASTM standard G-1-72. The polished and preweighed test coupons were exposed to the stimulated acidic environments for a total period of 48 h.

In each beaker containing the various concentrations of the acids, were suspended 4 samples each of the alloys and the set up allowed to stand for 48 h. A set of coupon was withdrawn 12 hourly, washed with distilled water, cleaned with acetone and dried in open air. The final weight of each of the test coupon was determined using the digital analytic weighing balance. Then the weight loss also calculated to enable calculation of the corrosion penetration rate in millimeter per year (mm/year) which, was calculated using the weight loss measurements and Eq. 1.

Weight Loss Characterization

A trend of direct relationship between the calculated weight loss values and the various concentration media. The material degradation increased as the percentage of the reinforcing phase increased in all the simulated media. This may be attributed to the increased mismatch between aluminium and manganese manifested in the grain boundaries leading to the formation of eutectic phase and hence bimetallic corrosion; as grain boundaries are known to be favourite sites for increased corrosion reaction kinetics, especially for binary alloys.

Effect of Alloy Composition

From the Table 1 of the corrosion rate data calculated, it can be inferred that the percentage of the reinforcing phase diminished the corrosion resistance of aluminium. This is evident because, the weight loss increased as a function of the percentage of manganese in the alloy systems in all the environments. This is in agreement with previous works (Ekuma, 2006; Idenyi et al., 2006) that alloying elements acts as impurities and indeed reduces the degree to which aluminium resists corrosion in stimulated environments.

Table 1 Corrosion rate data for the various Al-Mn alloy in 0.25 M HCl concentrations

Table 2 Corrosion rate data for the various Al-Mn alloy in 0.5 M HCl concentrations

Table 3 Corrosion rate data for the various Al-Mn alloy in 1.0 M HCl concentrations

Alloy

An alloy is considered as the combination of metal with at least one other mental or non-metal. Now, this combination needs to be segment of solid solution, a mixture or compound with another non-metal or mental for considering the alloy (Hossain et al. 2018). It is to be noted that metal alloys are being used specifically for enhancing both chemical and mechanical properties. Alloying elements can get added to the metal for increasing properties like; corrosion resistance, hardness, strength, machinability and others.

Properties of Manganese as Alloying Agent

It is to be noted that the wider part of manganese has been used as the high-carbon and added within the carbon steels. Now, the medium or low electrolytic manganese are being implemented in the lower carbon of steels content (AZO Materials, 2021). Here, manganese acts as the desulfurizer which forms up stable, sulfide particles of high melting and considering manganese as alloying agent increases up strength, hardness, and hardenability and abrasion resistance. Following are the key advantages of manganese considering as the alloying components:

  • This metal act like an active deoxidizer
  • Less likely to get separated than getting other alloying elements
  • It increases up the machinability through the integration with sulfur in forming up soft inclusion within the steel (AZO Materials, 2021)
  • It enables the consistency in building up edge with the place for chip for breaking
  • It also involved in enhancing production in steel mill through the integration with sulfur in the steel (AZO Materials, 2021)
  • It also involved in reduction of forming iron pyrite which can further make steel susceptible in tearing and cracking during the rolling process of temperature
  • This involves in boosting up the hardenability and tensile strength however decreases up the ductility
  • When getting integrated with sulfur it form the globular manganese sulfides which are needed in steel cutting process for ensuring up good machinability

Effect of Corrosion on Aluminium

If aluminium is exposed to very strong acid or alkaline environments outside the pH range 4 to 9, violent corrosion will occur in the form of metal pitting. Bases break down the aluminium faster than acids – for example concentrated caustic soda reacts so violently with aluminium that it can start to boil.

This chapter examines the issues concerning what is corrosion and why does alumi- num corrode. Corrosion is the chemical reaction of a metal, in this case aluminum, with its environment, which leads to the deterioration of the properties of the aluminum. Aluminum is a very reactive metal, but it is also a passive metal. This contradictory nature is explainable because nascent aluminum reacts with oxygen or water and forms a coherent surface oxide which impedes further reaction of aluminum with the environment, Aluminum is chemically very reactive. For example, powdered aluminum is used as rocket propellant for propulsion of the space shuttle’s solid fuel rockets. Additionally, the reaction of aluminum with water releases a tremendous amount of energy:

Al -l- 3H,O —+ AI(OH) -F 3H2† ΔG = — 1.1 MJ/Mol

In the above equation, one pound of aluminum reacting with water can release the energy equivalent to nine pounds of dynamite. The aluminum metal is converted from the bauxite ore only by the input of a large amount of elec- trical energy and heat. In turn, aluminum metal has a similar driving force to return to its hydroxide state. Corrosion is the reaction of aluminum with water and the subsequent deterioration of its properties. Corrosion, by definition, is a slow process, requiring days or years to occur to a noticeable extent, as opposed to similar elec- trochemical reactions such as etching, brightening, or anodizing which occur in minutes or less.

Figure 1 The Pourbaix Diagram for aluminum and water illustrates the stable phases for the different potentials and pHs. .

centration. The 0 line denotes a unit chemical activity (10 ) which would be a satu- rated ionic solution in contact with the solid phase. The — ó denotes a very dilute solution (10 6), roughly 1 ppm of the ionic species in contact with the solid phase. By using the Pourbaix diagram, one can explain why aluminum corrodes (dissolves) in liquid concrete, but is stable in solid concrete (assuming no salt is pre- sent). Concrete has a pH = 13, which on the Pourbaix diagram corresponds to the region where AlO,with an activity of 0.01 (10 ‘) is stable with solid gibbsite (hydragillite). In liquid flowing concrete, it is difficult to maintain an activity of 0.01 of AlO, , so the aluminum continuously dissolves. However, in solid concrete, solid state diffusion is very slow, and the aluminum concrete interface can become saturated in ionic species, which are immobile, and prevent further dissolution.

The Pourbaix diagrams illustrate that in fresh water aluminum will be passive, assumint there are no halide ions such as chlorides present. (The effect ofchlorides is described in later section.) The Pourbaix diagrams illustrate that

Figure 2 The dissolution-precipitation mechanism of aluminum corrosion

The dissolution-precipitation mechanism of aluminum corrosion. The aluminum dissolves as a cation at the anode. The electrons travel through the metal to the cathode where they are consumed by the cathodic reaction. The aluminum cation and the hydroxyl anion combine in the liquid and precipitate as a solid.

these diagrams show the equilibrium state, but predict nothing about the rates of reaction (fast versus slow). Second, even if the bulk solution has a neutral pH, aluminum can still corrode via localized corrosion since pits or crevices can have a diffrent pH and chloride concentration than the bulk solution.

Electrochemlstry of Corrosion

Aluminum corrosion is an electrochemical reaction, not simply a chemical reaction. Electrochemical means that the reaction depends on a transfer of electrons from one sire, the anode, where aluminum is dissolving and releasing electrons, to a second site, the cathode, where the electrons are consumed. The reaction for the anodic dissolution of aluminum is shown in Eq.

Al —+ Al+3 -t- 3e (anodic reaction)

The cathodic reaction on the other hand consumes the electrons. In water there are two possible cathodic reactions. If oxygen is present, the cathodic reaction is the reduction of oxygen in which oxygen is reduced to hydroxyl anions. This cathodic reaction will cause an increase in the pH at the surface:

1/2O2+ H2O +2e- —+ 2OH- (cathodic reaction)

The reduction of oxygen is a fairly rapid reaction when it occurs on impurities such as Fe or Cu precipitates in the aluminum matrix. For this reason, single phase aluminum alloys will have greater corrosion resistance than aluminum alloys which contain second-phase intermetallic particles.

If there is no oxygen present, the second possible cathodic reaction in water is

hydrogen evolution:

(cathodic reaction)

react with hydroxyls or water, and precipitate out as aluminum hydroxide, as shown in Fig. 10 and Eq. (8).

AlClt + 3OH —+ Al(OH) -t- 3CL*

Figure 3 The surface of aluminum after one day in hot water (62’C.) (B) Schematic of the multilayered hyroxides film on aluminum

Chloride anions are released from the cluster and return to the pit to continue the dissolution-precipitation reaction. As verification of this model, Wong and Alkire measured the solution in the the aluminum pits and demonstrated that

they contained aluminum hydroxyl-chlorides, AlC1g(OHJ3- Thus an entire range of aluminum hydroxyl-chlorides are possible.

Uniform Corrosion

General corrosion, or uniform corrosion, occurs in the solutions where pH is either very high or very low, or at high potentials in electrolytes with high chloride concentrations. In acidic (low pH) or alkaline (high pH) solutions, the aluminum oxide is unstable and thus non-protective. It demonstrated that aluminum dissolves rapidly in both high pH (e.g. caustic etching in sodium hydroxide) or low pH (e.g. dissolution in hydrochloric acid). Notably there are a few exceptions, as seen in Fig. S. The second case of uniform dissolution, can occur in a high chloride concentration with a high applied potential (voltage), The remedy for uniform corrosion is to change the electrolyte, use cathodic protection, add inhibitors, or replace the aluminum with a more corrosion resistant alloy.

Galvanlc Corrosion

Economically, galvanic corrosion creates the largest number of corrosion problems for aluminum alloys. Galvanic corrosion, also known as dissimilar metal corrosion, occurs when aluminum is electrically connected to a more noble metal, and both are in contact with the same electrolyte . The Galvanic Series in Flowing Seawater from the ASM Handbook Volume 13. The alumi- num alloys exhibit corrosion potentials between — 0.6 V and — 0.8 V versus the Saturated Calomel Electrode (SCE). The exact corrosion potential of an aluminum

Crevice corrosion can occur in a saltwaler environment if the crevice becomes deaerated, and the oxygen reduction reaction occurs outside of the crevice mouth. Under these ronditions, the crevice becomes more acidic, and corrosion occurs at an increasing rate gap between a bolt and a structure. When aluminum is wetted with the saltwater and water enters the crevice, little happens initially. Over time, inside the crevice oxygen is consumed due to the dissolution and precipitation of aluminum . If the crevice is narrow and the inward diffusion of oxygen is restricted, oxygen becomes depleted, and the crevice becomes acidic via the precipitation reaction. This acidic environment contains H“ cations which attract ani- ons in order to maintain the electrical neutrality of the crevice environment. The hydroxyl anions, OH , diffuse slower and loose the crevice race to the faster Cl anions. The crevice, which was originally neutral gradually becomes acidic due to the formation of a dilute hydrochloric acid environment. The anodic dissol- ution of aluminum accelerates inside this acidic crevice, and the cathodic reaction, oxygen reduction, occurs outside of the crevice mouth. Crevice corrosion is often called “autocatalytic” since it is self-accelerating.

The crevice in the above description is acidic. Crevices can be instead slightly

alkaline if the outside of the crevice has a good coating or is always dry. If the oxygen reduction reaction can not occur external to the crevice mouth, then the cathodic reaction must occur inside the crevice. In the absence of oxygen, the cathodic reaction would be hydrogen evolution in an acid in a neutral solution. This reaction would push the crevice alkaline, and corrosion would occur at a slower rate than the acidic crevice with the external cathode.

2H,O + 2e —+ Hz+ 2OH (cathodic reaction)

The best way io prevent crevice corrosion is also on the drawing board. The designer should eliminate crevices and gaps by continuous welding, or sealing the crevices with sealant, or allowing drainage. The outside should be coated to minimize the area available for the cathodic reaction. Maintenance by waxing or repainting minimizes the external cathodes, and seals the crevices which would pre- vent the occluded cells from initiating and growing.

Pitting Corrosion

Pitting corrosion is very similar to crevice corrosion. Pitting of aluminum alloys occurs if the electrolyte contains a low level of chloride anions, and if the alloy is at a potential above the “pitting potential.” Much research has been conducted

Intergranular Corrosion

Intergranular corrosion is a special form of corrosion characterized by the prefer- ential attack of the grain boundaries. Intergranular (IG) corrosion is also referred to as intergranular attack (IGA). IG corrosion only occurs if the grain boundary regions are compositionally different from the bulk of the alloy. This compositional difference occurs during heat treating, aging, or welding by diffusion of atoms and precipitation of second phase particles.

TEM micrograph showing the preferential dissolution of the grain boundary region, leaving the Al-Cu precipitates suspended in the corrosion product. TEM photographs by Ray Kilmer. micrograph in Fig. 20 where the TEM foil was etched in a dilute HCl solution . The grain boundary (white arrow) contains Al-Cu precipitates, which remain after the depleted grain boundary region is dissolved. The different types of intergranular corrosion for different aluminum alloys.

Intergranular corrosion can be prevented by using a single phase alloy, however, this is not always possible. Proper heat treatments can minimize the dif- ferences in potential between the bulk alloy and its grain boundary. For example in the 6000 alloys, the T6 temper often shows better IG resistance than the T4 temper. If a 2000 alloy is solutionized and not quenched rapidly, then precipitates may form on the grain boundaries and lead to IGA. Adhesive bonding is preferable over welding since the welding causes uncontrolled heat treatments and precipitation of second phases in the heat affected zone (HAZ). Eliminating the sites of pitting or crevice corrosion will also stop the initiation of IG corrosion.

Exfoliation Corrosion

Exfoliation corrosion is a special form of intergranular corrosion which occurs when the grains are flattened by heavy deformation during hot or cold rolling, and where no recrystallization has occurred. Exfoliation corrosion has the appearance of leaves of a book. A plate of alloy 7075-T6 afler six years of seacoast exposure. The 0.75 in thick plate was machined to the mid-plane leaving a plate of 0.375 in thickness. This plate was exposed at the seacoast in the bare condition, and the left side swelled to approximately four times the original thickness. Exfoliation is characteristic for the 2000 (Al-Cu), 5000 (Al-Mg), and 7000 (Al-Zn) series alloys which have grain boundary precipitation or depleted grain boundary regions.

Figure 4 Exfoliation of alloy 7075-T6 after six years seacoast exposure in the bare con- dition.

Erosion-corrosion of a water-cooled, alloy 6061-T6 heat sink used for cooling electronic equipment. The pH of the cooling water was > 9 which led to the dissolution of the aluminum peaked in 1950 with alloy 7178-T651 used on the Boeing 707, then the industry changed to using lower strength alloys. The yield strength of the upper wing skin did not exceed the 1950 level until the Boeing 777 in the l990s. The reason lower strength alloys were selected for the Boeing 747 and the L-101 I was that the aircraft designers chose an alloy with better SCC resistance rather than the higher yield.

The SCC crack velocity is very high in alloy 7079-T651 in 3.5% NaCl snlulions. (From Ref. 20b, used by the permission of ASM International.) along high angle grain boundaries. The stresses in the short transverse direction have much lower SCC threshold levels than stresses in the other directions.

Transgranular stress corrosion cracking (TGSCC) has been observed occasion- ally on aluminum alloys. It was first reported on alloy 7050-T73651 (Lifka,2005) and has since been documented on alloy 5182 soda can ends which blew out during storage in the high humidity summer months (Burleigh, 2001), TGSCC is character The crack growth velocity for 7075-T6 increases with increasing humidity. (From Ref. 20b, with permission from ASM International.

cycles, high purity 7075-T6 alloy can withstand a stress of 270 MPa in a vacuum or in dry nitrogen, but can withstand only 180 MPa in humid air or humid nitrogen. The presence of water vapor decreases the fatigue life.

Every aluminum alloy is affected by corrosion fatigue. The ratio of fatigue strength (after 10 cycles) in air versus in 3% NaCl solution for alloys 5087-H34, 5086-H36, 6061-T6, 7075-T73, and 2024-T3 [23]. Alloy 6061-T6 had only 55’% of the fatigue strength as in air, while alloy 2024-T3 had only 25% of the fatigue strength.

Fillform Corroslon

Filiform corrosion (also known as wormtrack corrosion) is a cosmetic problem for painted aluminum. Pinholes or defects in the paint from scratches or stone bruises can be the initiation site where corrosion begins with salt water pitting. Filiform corrosion requires chlorides for initiation and both high humidity and chlorides for the propagation of the track. The propagation depends on where Characteristic fatigue striations found on the fracture face of 2024-T3 fatigued in dry air.

The filament must be initiated by chlorides, and then it proceeds by a mechanism similar io crevice corrosion. The head is acidic, high in chlorides, and deaerated and is the anodic site. Oxygen and water vapor dirr»se through the filiform tail, and drive the cathodic reaction. Filiform corrosion can be prevented by sealing defects with paint or wax, and keeping the relative humidity low.

Microbiological induced Corrosion

Microbiological Induced Corrosion (MIC) applies to a corrosive situation which is caused or aggravated by the biological organisms. A classic case of MIC is the growth of fungus at the water/fuel interface in aluminum aircraft fuel tanks [30). The fungus consumes the high octane fuel, and excretes an acid which attacks and pits the aluminum fuel tank and causes leaking. The solution for this problem is to control the fuel quality and prevent water from entering or remaining in the fuel tanks. lf fuel quality control is not feasible, then fungicides are sometimes added to the aircraft fuel.

CORROSION PREVENTION

The forms of aluminum corrosion and a few selected methods for corrosion prevention were discussed. The general methods for corrosion prevention of aluminum alloys.

The second factor to be considered during the design stage is the shape of the final product. The design should provide water runoff (no standing water) without crevices or sharp corners where the coating can be damaged. Figure 38 illustrates different designs to avoid liquid entrapment [2]. The designer should also avoid dis- similar metal contact and provide for the sealing of all fasteners, rivets and crevices.

Welds and Heat Affected Zones (HAZ)

Welded joints are a weak spot for many aluminum alloys. It is not possible to weld many aluminum alloys such as the 2024 and the 7075 due to phase segregation and cracking. For other alloys the heat affected zone (HAZ) is particularly problem-prone due to the precipitation of second phases. The HAZ is the zone between the weld metal and the unaffected base metal, where the metal has been healed, but not melted. This heating has lead to the precipitation of many second phases along the grain boundaries and the corresponding depleted zone adjacent to the grain boundaries. This HAZ is prone to intergranular corrosion.

To prevent preferential dissolution of the weld metal, the weld metal should be slightly more noble than the base alloy. Hatch {2] provides extensive tables for weld metal specifications.

Regular Maintenance

The aging aircraft program has demonstrated lhat a aircraft must be maintained adequately or the plane will be lost to corrosion. If the plane is carefully maintained, then its service life can be indefinite. Maintenance consists of inspecting for corrosion damage, and repairing the damage before the problem gets significant. The com- mercial airlines dismantle and inspect the aircraft during the “D-Check” [31]. Unpublished tests reported that a bare aluminum panels which were wiped with @00 steel wool and automotive wax on a regular basis maintained its shine for over ten years of semi-industrial outdoor exposure .

Coatings

Coatings are a standard method of protecting an aluminum structure against corrosion. (The old corrosion prevention adage, “Paint it!” is valid.) Polymers, (e.g. acrylic or polyurethane) are commonly used for the top coat. However the problem is keeping the polymer attached to the aluminum base metal. For this reason, a good coating usually consists of multiple layers, each with their own particular function. The initial coating on ltte bare aluminum is a primer or a conversion coating. The function of the primer is to chemically react with the base metal to form a rough surface layer with which the polymer coating can bond chemically and mechanically. Chromate conversion coats such as Alodine were used in the past, but these are being replaced by non-chromate conversion coats. The automotive industry uses zinc phosphate conversion coats because it works for both steel and aluminum body sheet. For use with aluminum, the zinc phosphate bath must contain fluorides in order to precipitate the dissolved aluminum which can poison the reaction.

Stress Corrosion Cracking (SCC)

Stress corrosion cracking (SCC) is the bane of aluminum alloys. SCC requires three simultaneous conditions, first a susceptible alloy, second a humid or water environment, and third a tensile stress which will open the crack and enable crack propagation. SCC can occur in two modes, intergranular stress corrosion cracking (IGSCC) which is the more common form, or transgranular SCC (TGSCC). In IGSCC, the crack follows the grain boundaries. In transgranular stress corrosion cracking (TGSCC), the cracks cut through the grains and are oblivious to the grain boundaries.

The general trend to use higher strength alloys peaked in 1950 with alloy 7178-T651 used on the Boeing 707, then the industry changed to using lower strength alloys. The yield strength of the upper wing skin did not exceed the 1950 level until the Boeing 777 in the 1990s. The reason lower strength alloys were selected for the Boeing 747 and the L-1011 was that the aircraft designers chose an alloy with better SCC resistance rather than the higher yield strength.

Corrosion Fatigue

Corrosion fatigue can occur when an aluminum structure is repeatedly stressed at low stress levels in a corrosive environment. A fatigue crack can initiate and propagate under the influence of the crack-opening stress and the environment. Similar striations may sometimes be found on corrosion fatigued samples, but often the subsequent crevice corrosion in the narrow fatigue crack dissolves them.

Fatigue strengths of aluminum alloys are lower in such corrosive environments as seawater and other salt solutions than in air, especially when evaluated by low-stress long-duration tests. Like SCC of aluminum alloys, corrosion fatigue requires the presence of water. In contrast to SCC, however, corrosion fatigue is not appreciably affected by test direction, because the fracture that results from this type of attack is predominantly transgranular.

Microbiological Induced Corrosion

Microbiological Induced Corrosion (MIC) applies to a corrosive situation which is caused or aggravated by the biological organisms. A classic case of MIC is the growth of fungus at the water/fuel interface in aluminum aircraft fuel tanks. The fungus consumes the high octane fuel, and excretes an acid which attacks and pits the aluminum fuel tank and causes leaking. The solution for this problem is to control the fuel quality and prevent water from entering or remaining in the fuel tanks. If fuel quality control is not feasible, then fungicides are sometimes added to the aircraft fuel.

Anodlzing

Other types of conversion coating are anodizing and the electrocoat (E-coat). The science of anodizing has been covered by many authors (Wernick, [32]). In anodizing, the aluminum is immersed in an electrolyte (phosphoric acid, borate-boric buffer solution, sulfuric acid, oxalic acid, or chromic acid) and an anodic voltage is applied to the aluminum part. The aluminum reacts and gfows a thick anodic oxide on the surface which consists of a barrier layer and a porous layer (Fig. 39). The porous layer can be colored with dyes and sealed by boiling in water to close the pores with aluminum hydroxide. The electrocoat is a rapid form of anodizing and polymer coating simultaneously. The E-coat is sprayed on to the positively charged aluminum, and the anodized layer is grown with the E-coat polymer.

Another form of anodizing has been reported by Kuznetsova et aI. [33]. The

group exposed pure aluminum in a vacuum to water vapor, and then to an electron beam at 100 V and lhe resulting oxide was thin but highly resistant to corrosion.

Alcladdlng

Alcladding is the term which first described the cladding of 2024-T3 aircraft fuselage skin with a commercial purity aluminum sheet. Alloy 2024-T3 contains 4Z» Cu, which age-hardens and forms Al,Cu precipitates, which provide strength, but deteriorate the corrosion resistance. To prevent the high corrosion rate, 2024 is clad with pure aluminum, which is galvanically more anodic than the copper containing alloy (see Table 1), and so it sacrificially corrodes and protects the 2024 base alloy, Fig. 40 [34]. The alcladding is produced by hot rolling thin aluminum sheets on to the iop and bottom of the 2024-T3 sheet. This aluminum sandwich is reduced in thickness, and the oxide film breaks, allowing nascent aluminum to meet and form a metallurgical bond. The pure aluminum outer layer has a more negative corrosion potential than the 2024-T3, so it acts as a sacrificial anode, preferentially corroding and protecting the 2024. This sacrificial protection is seen in Fig. 40 [34].

The ideal Corrosion Reaietant Aluminum Alloy

The ideal corrosion resistant aluminum alloy would be single phase and homogenous. However, strengthening of aluminum requires second phases for grain boundary pinning, and precipitation hardening. Therefore the ideal aluminum alloy would contain inert, insulating, second phase particles (e.g. aluminum oxide) to avoid galvanic corrosion problems.

CORROSION TEST METHODS

Introduction to Test Methods

Corrosion tests are necessary in order to predict the service life of an aluminum alloy or product in a given environment. However, it is often difficult to design a correct corrosion test, and to correctly interpret the results. Every metal will cofrode somewhere, especially when given sufficient time, The choice of the correct corrosion test depends on service environment where the aluminum product will operate. For example, an aluminum automobile wheel will be subjected to corrosion and cyclic fatigue in all four seasons, ranging from the humid and hot summer drive to the beach, to the salt saturated slushy snow spray on the city streets in the winter. How does one choose a corrosion test to evaluate the aluminum wheel in this service environment? Because of the complexity of service environments, numerous corrosion tests have been designed. Below is a brief review of the common tests for aluminum alloys and products. The author recommends using triplicate samples in triplicate tests before making any decision which carries a signihcant economic price tag. Making an important alloy decision based on the result of one or two samples tested with one method is inviting disaster.

Exposure Tests

The Alternate Immersion (ASTM G44) [17] is a cyclic test with the aluminum samples hourly immersed in 3.5% NaCl solution (10 mins) and then drying in air (50 mins). This cycle continues for 24 hr a day for 20-90 days. The American Society for the Testing of Materials (ASTM) has an extensive series of corrosion tests for aluminum alloys. Because aluminum is most susceptible to chloride pitting, the ASTM tests generally include some form of saltwater.

The classic corrosion test is the salt spray test in the saltwater fog cabinet, ASTM BI 17 [17]. The Saltwater Fog consists of leaving the sample continuously exposed to a mist or spray of saltwater for up to six weeks. This test imitates the conditions near a beach or in an automobile wheel well, and is used commonly for painted panels. This is an ideal test if the customer plans to use the aluminum product in a saltwater fog, but this does not necessarily correlate to any other environments. For example, filiform corrosion can initiate in the saltwater spray, but it does not propagate under the spray because of the 100% humidity.

Seacoast exposure is conducted by exposing the samples on open-air racks within sea-spray range of the ocean. The Aluminum Company of America (Alcoa) operates a seacoast exposure site at Point Judith, Rhode Island. The LaQue Center for Corrosion Technology has a commercial seacoast exposure site in North Carolina.

Paradoxically, aluminum oxidation is a central part of its corrosion resistance. Aluminum has a very high affinity to oxygen. When a new aluminum surface is exposed in the presence of air or any other oxidizing agent, it quickly develops a thin, hard film of aluminum oxide (or hydrated oxide in non-stagnant water). This aluminum oxidation is precisely what makes aluminum so corrosion-resistant.

This film is relatively inert chemically. The corrosion resistance of aluminum relies on the inactivity of this surface film of aluminum or hydrated oxide. It’s when this surface film dissolves that corrosion occurs; when the film suffers localized damage and self-healing cannot occur, localized corrosion follows.

This surface film is generally stable in a pH range of about 4.5 to 8. The film can stay stable in other cases depending on the environment, for example, nitric acid at pH 0, glacial acetic acid at pH3, or ammonium hydroxide at pH 13. The oxide film can be dissolved in most strong acids and bases, in which case the corrosion of the aluminum will be rapid.

As with all common architectural and structural, aluminum will corrode under certain conditions. This is more likely to occur when the wrong alloy is chosen for projects or applications. To get good results with aluminum, it is essential to know the following:

  • the conditions under which corrosion will occur
  • the form that the corrosion will take
  • the rate of corrosion
  • any preventative measures that can be taken

Rusting is a form of corrosion that’s specific to iron and steel (because it contains iron). In fact, rust is the common name for iron oxide, when iron or steel bonds with oxygen and undergoes oxidation. Therefore, aluminum can’t rust.

1xxx

Alloy 1100: Aluminum grade 1100 is commercially pure aluminum. It has excellent corrosion resistance and is common in the chemical and food processing industries. Otherwise, it is a soft and ductile metal with excellent workability. You’ll find alloy 1100 frequently in applications that require forming. It can be welded with any method, but it is non-heat-treatable.

3xxx

Alloy 3003: Alloy 3003 is the most common of the aluminum alloys. It is pure, commercial-grade aluminum with a 20% boost in strength thanks to the addition of Manganese and Copper. It also has excellent corrosion resistance, workability, and can be welded or brazed, drawn or spun.

5xxx

Alloy 5052: 5052 is also a very popular alloy because it has the highest strength of any of the non-heat-treatable grades. It is especially common in marine and saltwater atmospheres because of its resistance to corrosion. It has excellent workability and is easily drawn or formed into complex shapes.

6xxx

Alloy 6061: 6061 is the most versatile of the heat-treatable alloys, including corrosion resistance, workability when annealed, and weldability. You’ll find alloy 6061 in products and applications that require a trifecta of good appearance, better corrosion resistance, and good strength.

Alloy 6063: 6063 is usually known as an architectural alloy because of its high tensile, great finishing, and high corrosion-resistant properties. You’ll find 6063 in interior and exterior architectural settings and trims. It is frequently anodized.

The Aerospace Industry (2xxx & 7xxx)

In the aerospace industry, there’s a need for both high strength and high corrosion resistance. For this reason, the aerospace industry is generally confined to the 2xxx and 7xxx series of aluminum. We get around the reduced corrosion resistance of alloyed aluminum in these series through alclad liners that are pure aluminum and alloyed to the stronger aluminum alloy underneath. The pure aluminum gives the plane the corrosion resistance that’s needed without compromising the strength of the structural aluminum.

Alloy 2011: Alloy 2011, otherwise known as Free Machining Alloy (FMA), is known for its high mechanical strength and excellent machining, which is why you see it in complex and detailed parts. If this alloy is machined under high-speed, it will produce fine chips, but they’re easily removed.

Alloy 2014: Alloy 2014 is copper-based with very high strength and excellent machining. You’ll find it in many structural aerospace applications because of its high corrosion resistance.

Alloy 2024: Alloy 2024 is very commonly used because of its combination of high strength and excellent fatigue resistance. You’ll find it wherever products require a good ratio of strength to weight. But, it’s corrosion resistance is fairly low, so you’ll often see it with either an anodized surface (see below) or with Alclad.

Alloy 7075: Of all of the aluminum alloys, 7075 is one of the highest strength alloys. Like 2024, it has an excellent ratio of strength to weight and is used in parts that will undergo high stress. 7075 can be formed when annealed and then heat-treated if needed.

Aluminum oxidation happens faster than steel oxidation because aluminum has a strong affinity for oxygen. When all the aluminum atoms have bonded with oxygen, the oxidation process stops.

Rather than flaking through like rust, aluminum oxide just forms a hard, whitish-colored surface skin.

Since aluminum so readily bonds with oxygen, there’s little that can be done about aluminum oxidation. Aluminum corrosion, however, can be a serious problem. To prevent aluminum corrosion, you should consider:

First and foremost, choosing the correct alloy: some alloys, like 5052 and 3003, have better corrosion-resistance than others. You can read here about the difference between 5052 and 3003. In general, 1xxx, 3xxx, 5xxx offer the best corrosion resistance.

Consider alclad liners common in the aerospace industry

Applying a protective coating

Minimizing the effect of galvanic corrosion. Galvanic corrosion is caused by putting two dissimilar metals, like aluminum and steel, next to each other.

Protective Coatings

Generally, there are three types of protective coatings appropriate for aluminum:

  • Paint
  • Powder coat
  • Anodizing

The effect of Mn on the mechanical behavior of Al alloys

Manganese has been known to be an alloying element of Al alloys that contributes to uniform deformation. Recently, it was found that as the manganese content increases over 0.5 wt.% in such aluminum alloys as the 6000, and 7000 series alloys, both yield and ultimate tensile strength increase significantly without decreasing ductility. The added manganese forms a manganese dispersoid of Al6Mn. This dispersoid has an incoherent structural relationship with respect to the matrix, FCC, in retarding the motion of dislocations that increase strength. Once the dislocation is blocked by the dispersoid, it tends to change the slip system by means of cross-slip. This cross-slip allows the deformation to maintain uniformly good ductility. TEM observation has proven the above mentioned activities of dislocation by analyzing the characters of the dislocations around and away from the dispersoids. Adding manganese to aluminum alloys not only enhances tensile strength but also significantly improves low-cycle fatigue resistance. Corrosion resistance is also measurable improved by the addition of manganese. After extrusion, the recrystallization is also retarded so that a very small grain size is maintained, contributing to an improvement in the mechanical properties. (Nam, 2000)

Some studies suggest that the alkalinity developed at cathodic IMPs on Al alloys in aerated solutions can dissolve the adjacent alloy matrix, creating grooves or pit-like clusters [9,10]. Later on, these cavities may switch to an acid-pitting mechanism. Other authors, however, refer to the alkaline attack as pitting or treat the problem as galvanic corrosion between particles and matrix [11,12], or self-regulating cathodic reaction occurring on the particles [12]. Electrochemical behavior of Al3Fe phase in Al-Mn-Fe-Si system in high pH NaOH solution revealed that near the corrosion potential, Al3Fe phase undergoes a selective dissolution of Al and the surface of Al3Fe crystals becomes richer in Fe, which is a detrimental for the cathodic behavior of this type of IMPs. The presence of Mn or Si in the Al3Fe, such as α-Al(Fe,Mn)Si and δ-AlFeSi phases, reduces the effects of Fe both as regards anodic and cathodic reaction rate [10]. The positive effect of an increase of Mn in Al-Mn alloy in a solid solution leads to a shift of the potential of matrix to the cathodic direction, while an increase in the Mn/Fe ratio of the IMPs shifts their potential to the anodic direction. Therefore, as net effect, the potential difference between the matrix and the IMPs decreases [13].

In this series of alloys, Manganese is the major alloying element, and small amounts of magnesium are added in many alloys in this series. The maximum solubility of Mn is only 1.82% so the alloying range is limited. They are non-heat-treatable alloys and show great ductility. This, along with a moderate strength makes them of interest in many applications, although limited alloys are commonly used. Particularly, the 3003 and 3004 alloys are manufactured in sheets and are used for household appliances and beverage cans, respectively. These alloys have excellent corrosion resistance but are quite sensitive to the presence of iron impurities because it degrades both, corrosion performance and ductility of the alloy. The presence of magnesium provides solution strengthening and tensile strengths of up to 280–320 MPa can be achieved in some systems (Table 3).

The main strength of these alloys is the corrosion resistance, so to solve their lower mechanical properties either the use of them in aluminum matrix composites (Gallegos-Orozco et al., 2020) and the addition of alloyants to form dispersoids in the matrix (Li et al., 2018), are being considered.

Wrought aluminium is identified with a four digit number which identifies the alloying elements. Cast aluminium alloys use a four to five digit number with a decimal point. The digit in the hundreds place indicates the alloying elements, while the digit after the decimal point indicates the form (cast shape or ingot)

Alloys were produced by induction melting and the starting materials were high purity metals (>99.9%). Following melting, alloys were poured into a cast iron mould and allowed to cool. Several samples with low impurity levels were also examined to form a benchmark from which the effects of the alloying additions on the change in corrosion resistance can be measured. The levels of alloying additions in each of the samples tested. Compositions were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) by Spectrometer Services (Coburg, Vic, Australia).

Specimens were ground to a 2000 grit surface finish. A 3-electrode electrochemical flat-cell with an exposed sample area of 1 cm2 was used for electrochemical testing. The test electrolyte was 0.1M NaCl in all cases. A VMP 3Z potentiostat was used, with potentiodynamic polarisation carried at 1 mV/s. Prior to polarisation, samples were conditioned for ten minutes at open circuit to ascertain a stable potential. The polarisation curves were used to determine icorr (via a Tafel-type fit) using EC-Lab software. Such fitting is inherently difficult, however the ability of EC-lab to allow manual control is critical. As a general rule, fits were executed by selecting a portion of the curve that commenced >50mV from Ecorr, and icorr was subsequently estimated from the value where the fit intercepted the potential value of the true Ecorr. This fit was generally dominated by cathodic data because the cathodic branch of the Tafel plot varied more widely between specimens. More so, polarisation testing was also able to visually reveal comparative information related to the kinetics of both the anodic and cathodic reactions between alloys. Each sample was tested five times and an average result was determined. Weight loss testing was also carried out by immersion of specimens in 0.1M NaCl. Samples were cleaned in 7% HNO3 for approximately 5 seconds to remove any corrosion product, prior to mass loss determination.

In order to present the relative effects of both the elements being studied herein, the presentation of data as contour plots is presented such that visual assessment of the overall test results may be obtained. The darker (viz. tending to dark blue) areas display regions with lower corrosion rates where increasing brightness (viz. tending to red) on the contour plots predicts an increase in the overall corrosion rate. The grey dots on the contour plot correspond to the relative spread of the samples tested. Figure 1 shows the contour plot of the AL-Mn specimens containing Mn and Al against their immersion weight loss values in grams per centimetre squared per day. As Al content is increased there is a corresponding increase in the observed corrosion rate. However, as Mn is increased the corrosion rate initially decreases before starting to increase again at higher levels. The effect on the corrosion rate cause by the addition of Mn continues in the presence of higher Al levels in the alloy. The lowest commercially practical corrosion rates are seen in a diagonal band that corresponds to a Al:Mn ratio below roughly 0.036.

Figure 5 corrosion rate as a function of Mn vs. AL presented from weight loss data

Effect of Mn content on the microstructure and corrosion resistance of Al-Cu-Mg-Mn alloys was examined by optical microscope (OM), scanning electron microscope (SEM), tensile tests, pitting corrosion and electrochemical tests. It is shown that increase of Mn content can accelerate the aging process of the Al-Cu-Mg-Mn alloys, which is beneficial to shorten heat treatment time. Polarization curves indicate that the corrosion current density and corrosion rate of Al-4Cu-2Mg-1.2Mn alloy are the lowest compared with Al-4Cu-2Mg-0.6Mn and Al-4Cu-2Mg-0.9Mn alloys for both the as-cast and heat-treated conditions. Electrochemical impedance spectroscopy (EIS) tests also demonstrate that Al-4Cu-2Mg-1.2Mn alloy displays the highest resistance. The maximum pitting corrosion depth of the as-aged Al-4Cu-2Mg-1.2Mn and Al-4Cu-2Mg-0.6Mn alloys is about 65 µm and 110 µm, respectively. Therefore, Mn addition can improve the mechanical properties and corrosion resistance of the Al-Cu-Mg alloys.

Theory

VOF Method

Volume of fluid (VOF) method put forward by Hirt and Nichols is widely used in calculating the dynamics of free surface of two or more different fluid phases by solving the momentum equations and tracking (Sharnet,2017). VOF method can be only utilized for two or more fluids which are impermeable to each other and among all phases only one phase can be assumed to be compressible. In this thesis work, air and liquid aluminum are employed to be two immiscible phases. Moreover, in multiphase calculation VOF model can be also used in the Corrosion and melting process.

In general, a time-dependent volume fraction of each fluid phase in the computational cell can be computed by VOF calculation. In this thesis work, the volume fraction of liquid aluminum F in a control computational mesh grid can be defined as following three different conditions:

● F=0, this grid is filled with the air phase.

● 0<F<1, this grid is at the interface of two phases.

● F=1, this grid is filled with the liquid aluminum phase.

Turbulence Model

The k-epsilon model has been widely utilized to calculate the turbulence effects in the flow fields in metal industries. This model contains two major variables which are turbulent energy k and turbulent dissipation. The transport equations of realizable kepsilon model to calculate the turbulent behaviors of the flow field are described as following equations (Sharnet,2017):

Realizable k−ε model is a relatively new model on the basis of standard k−ε model. Realizable model computes the new equation of turbulent velocity and the new equation of ε is derived from the exact transport equation of the eddy fluctuation’s root-meansquare (Shih,1995). One of the advantages of the realizable k−ε model is this model satisfies the constraints on the Reynolds stress thus it can keep consistent with the Reynolds stress of real physics turbulent flow.

Corrosion Model

Corrosion and melting model is available in the Fluent which can be used for simulate the melting and Corrosion process by enthalpy-porosity method (Sharnet,2017). This model is not focus on the interface between different phase as VOF model and calculates the liquid fraction of fluid in each mesh grid of the computational domain. In the simulation of Corrosion process, the fluid domain will be considered as three regions, solid, fluid and mushy zone region. Mushy zone region contains the phase of which the liquid fraction is between 0 and 1.

Discrete Phase Model

DPM model is utilized to calculate the motion and path of particles in the fluid field. The boundary conditions for discrete phase consist of four types. Reflect model indicates the particles will get back to the fluid field when they reach the wall. Trap model means when the particles reach the wall they will get caught by the wall. Escape model is utilized if particles leave the fluid field when they reach the boundaries and this model is usually used for the inlet or outlet boundary of the fluid field. In addition, the final type is wall-jet model which is not used in this work.

Involvement of important engineering applications in the interaction of free-moving objects with dispersed multi-phase flows are numerous in recent years. However, due to the challenge and complexity, few studies have been reported and modeling approaches remain very limited. The use of discrete particle models (DPMs) for the study of the fluid flow phenomena and elaborates several different types of multiple phases. The efficiency of particle retention and computational time were considered in determining the most appropriate multiphase model. Therefore, the dynamic modeling of multi-scale systems requires a method to solve the problem of structural fluid interaction (FSI) in the particle fluid flow.

Many metallurgical processes involve multiphase flows and liquid metal processing is not an exception. During the secondary refining, and casting of steel, there are many interactions between the liquid phase, and the dispersed phases (spherical gas bubbles, inclusions, liquid slag droplets etc.). To mathematically model these operations, the Discrete Phase Method (DPM) is now being used by significant number of researchers. However, in certain publications, the equations presented are ambiguous but have nonetheless been referenced by many researchers. The present technical note highlights a mistake in the interpretation of the discrete phase equation in a technical paper by Hulstrung et al. 1 and also points out the mis-leading equation in the ANSYS-FLUENT 18.0 theory guide 2.

Research Methodology

Research Methodology is considered as the specific process or techniques used in selecting, recognizing, analyzing and processing information regarding the research topic. In this methodology section, the researcher will allow the reader in evaluating up the research study its overall reliability and validity.

Data Collection

Collection of data is procedures of measuring and gathering information based on the variables of interest, in an established systematic fashion which allows one in answering stated in research questions, evaluating outcomes and testing hypothesis (Snyder, 2019). The data collection element of research is very common towards all the fields of study both social and physical sciences, business and humanities. Regardless within the study field or preferences for defining data, there are mainly two kind of data collection method; quantitative and qualitative (Mohajan, 2018). The researcher will be implementing; qualitative secondary research. The data collection will aid the researcher in following:

  • Will provides the researcher ability in answering the research question in accurate way
  • Will provide the researcher in validating and repeating research study
  • Will help the researcher in findings results through the collected resources
  • Will help the researcher in pursuing up the fruitless avenues of further investigation
  • Will help the researcher in compromising up the decisions for public policy

Secondary Research

Desk or secondary research is considered to be research method which involves in using the existing data. The researcher has selected this secondary research method because it is very cost-effective as compared to the primary research. This secondary research will also provide the researcher with foundation of this research study (Nayak and Singh, 2021). This secondary research will help the researcher in evaluating the current landscape of the available information before moving towards the primary research method. This will help the researcher in saving money and time which may get better spent elsewhere.

Material and Methods

Numerical Assumptions

In order to perform the simulation of the sampling procedure more fluently and with considering the computer calculation time, several assumptions were made in this thesis work’s mathematical model.

● There are two fluid phases, air, water liquid and pure steel-melt and both of them are incompressible Newtonian fluids.

● Assume the mass flow rate is constant and the liquid is flowing automatically along the center axis.

● The injection particles size, concentration and density are assumed to be constant.

● The injected particles are steel and assumed to be spherical.

● The particle collisions and agglomeration in the computational domain are not considered.

● Assume there is no chemical reactions take place in the calculation domain.

● There is no contact resistivity in this system.

Material

For the sample material, the details have been taken from the American Elements.

The below data sheet specify the material properties

Product Datasheet

Aluminum Manganese Tubing

Product code: AL-MN-02-TU

Formula: Al-Mn

Molecular Weight:

Purity: (2N) 99%

Appearance: Gray metallic tubes

Melting Range: 585-650 [°C]

Boiling Point: N/A

Density: 2.72 g/cm3

Total Metal Impurities (max): 1.0%

Figure 6 Material Properties of Al-Mn Alloy tubing

Geometry

A three dimensional symmetric model of pipe was employed in this simulation work and the below figure shows the geometry of the pipe system which is mirror symmetry of the central axis. Tthe inner area is simulated to be fluid domain and outer areas are calculated as solid phase with the material of Aluminium-Mn Alloy.

Figure 7 Al-Mn Alloy Tube geometry

Mesh

In this geometry, the body sizing and inflation meshing has used. The Body Sizing control also has the ability to use geometric bodies themselves to control the mesh refinement (in ANSYS Meshing terminology, these are termed a “body of influence”). A body of influence can be of any arbitrary shape/size and intersects the main fluid domain that we are trying to mesh.

In ANSYS Fluent, you can achieving cell/element stacking in the direction normal to the boundary using a feature called Inflation. Essentially, you can inflate the mesh with several layers from the surface of the boundary until you cover the boundary layer thickness fully. Defeaturing size determine the size of features that mesher take into account when mesh generates and the sizes under that value will be ignored.

The different size of mesh have been taken. Firstly, the element size taken 0.01 m. After meshing it, the total skewness for few nodes and elements were exceeded. So by decreasing the size of the mesh, the acceptable mesh have been obtained.

Figure 8 Body sizing Mesh

Figure 9 Inflation Mesh Details

The total number of nodes and elements obtained with the element size 0.005m is 22278 and 48030 respectivley.

Figure 10 Meshing of the tubing


Numerical Models

A number of sub-computational models are used in this study since the simulations will be performed. The solver will be pressure based with absolute velocity formulation. The time of fluid flowing has set as steady. So that the velocity will be constant. Also, the in the solver the gravity to the pipe have been applied in the Z- Direction.

Firstly, in order to simulate corrosion process and observe the flow pattern of air and steel phases DPM method is used, which is to compute the movement of the free boundary between the air phase and liquid phase. The theory of DPM method has been summarized in the previous section. Furthermore, once the liquid steel start flowing inside the tube of the Al-Mn Alloy, the fluid flow will be affected by turbulence then the realizable k − ε model is also utilized. The figure below describes the constants setup for the realizable k − ε turbulence model in FLUENT.

Figure 11 Viscous Model

Figure 12 Discrete Phase Model

For setting up the injection properties, at inlet the fluid flow has setup.

Figure 13 Set Injection Properties

Finally, after simulating the Corrosion process during and after filling process, the inclusion particles distribution need to be computed by employing the Discrete Phase Model (DPM) , which is utilized to model the alumina particles motion and distribution in the al-melt. Two physical models in DPM are also used together in this simulation in order to make the simulation results to be physically more reliable. Pressure gradient force is the assumed to force in the particles. Due to the influence of this force, different position in the flow field will have different pressure, which is extremely important to make the heavier alumina particles precipitate in the lighter al-melt. Furthermore, the virtual mass force is another force used due to in the flow field a particle is moving and being accelerated. In addition, the discrete random walk model is also used to simulate the turbulence effects on the particles in the fluid domain.

Boundary Conditions

Inlet Boundary

The inlet boundary (as shown in Figure given below ) is set to be mass flow rate inlet with several different x-component mass flow rate values and different pressure. The boundary conditions at the inlet are described as follows for the initial simulation:

1) Mass Flow rate = 2 Kg/s;

2) Pressure = 10100 Pa;

3) Direction Specification Method = Normal to Boundary

Outlet Boundary

The outlet boundary is set to be pressure outlet for the gas phase. Zero Pa is utilized for

the outlet boundary conditions and the temperature of the gas coming out is set to be

800K. In addition, the influence of this boundary on the particle is set to be escaped.

Inner Wall Boundary

Inner wall is set to be stationary wall with Coupled conditions, these boundaries will

reflect the particles.

Outer Wall Boundary

Outer wall is set to be mixed wall and the boundary conditions at the outer wall are

summarized as follows:

1) Heat transfer coefficient = 20W/m2-K;

2) Temperature = 300K;

3) Emissivity = 1.

Methods of Solutions

The CFD software FLUENT 19.0 (Student Edition) is used to solve the governing equations and boundary conditions. Coupled scheme is used for pressure-velocity coupling calculation. And the PRESTO discretization method is used for solving the pressure. In addition, the second order upwind discretization schemes are applied for calculating the momentum and energy equations. Other parameters are calculated by first order upwind discretization schemes with considering the simulation time.

Solution Initialization

The Solution Initialization task page allows you to set initial values for the flow variables and initialize the solution using these values. You can compute the values from information in a specified zone, enter them manually, or have the solver compute average values based on all zones.

Standard initialization allows you specify all the variables directly as initial guesses. Fluent is setup to allow you to easily specify the initial x-velocity, y-velocity, z-velocity, temperature, pressure, etc. all as constant fields over the whole domain.

Standard initialization is just filling the filed properties with constant values, while hybrid initialization solves a number of iterations (10) of a simplified equation system and thereby gets usually a better guess for the flow variables, in particular for the pressure field.

iter scalar-0

1 1.000000e+00

2 1.526896e-05

3 5.131697e-06

4 3.263197e-06

5 1.915184e-06

6 1.014217e-06

7 7.987701e-07

8 4.724921e-07

9 3.910735e-07

10 2.899177e-07

Result and Discussion

At mass flow rate = 2kg/s and Diameter of pipe = 63mm with wall thickness 3mm.

The erosion rate is defined as

Where C (dp) is a function of particle diameter, ∝ is the impact angle of the particle path with the wall face,

f ( ) is a function of impact angle, v is the relative particle velocity, b (v) is a function of relative particle velocity, and Aface is the area of the cell face at the wall. Default values are C = 1.8 * 10^-9, f = 1, and b = 0.The erosion rate is computed assuming reflecting wall boundary condition. For steel material n=2.6, Fs=0.2 (for fully rounded solid particles).

Figure 14 DPM erosion rate

The DPM concentration is defined as:

DPM concentration = (Avg. particle mass in cell * Part resi. Time * Strength of particle) / Cell volume …1

Strength of particle = number in parcel / dt_flow …2a

= total particle flow rate / mass of single particle in the stream ….2b

From equation 1 and equation 2b,

DPM conc. = (Avg. particle mass in cell * Part resi. Time * Total particle flow rate) / (mass of single particle in stream * cell volume) …..3

Sample Calculation

Consider the following example to make things more clear.

a. A simple channel flow with constant velocity of 1m/s is used.
b. The top and bottom surface are defined as symmetry to ensure the plug flow condition.
c. The particles with total mass of 0.1 Kg/s and velocity of 1m/s are injected as single injection at the center of inlet.
d. This ensures that DPM concentration is non-zero only at the center line and is zero everywhere else.

A single stream of particle is modelled, hence,

Average particle mass in cell = Average mass of particles in particle stream …4

From equations 3 and 4,

DPM conc. = Part resi. Time * Total particle flow rate / Cell volume

For the test case, Part resi. Time = 0.002 s, Total particle flow rate = 0.1 Kg/s, Cell volume = 2.08e-6 m3

DPM conc. = 0.002 * 0.1 / 2.081 e-6 = 95 Kg / m3

Figure 15 DPM concentration

The total pressure in FLUENT is based on a difference of the operating pressure. Any time FLUENT says static pressure, they are referring to gage static pressure. If you set OP = 0 then, obviously you are now at abs zero reference.The static pressure is usually defined as pressure of fluid at rest and dynamic due to its velocity or in other words due to kinetic energy of a fluid element. Now consider a case of flow in pipe (steady state and in-compressible fluid say water). I simulated one using fluent.

Figure 16 Static Pressure

User-defined functions can be used to describe erosion models of any form. For more complex models, such as those models with varying function angles,  , the default Erosion Model in the Wall boundary condition dialog box cannot be used. Hence, a user-defined function should be used instead. Note that the particle erosion and accretion rates can be displayed only when coupled calculations are enabled.

The accretion rate is defined as

Figure 17 DPM accretion rate

Particle Residence Time T = 1.5034s

Figure 18 Plot Particle Residence Time vs Time

Different Mass Flow rate

The Diameter of pipe = 63mm with wall thickness 3mm has kept constant

Mass Flow rate (Kg/s)Pressure(Pa)DPM erosion RateStatic Pressure (Pa)Particle Acceration RateDPM Concentration (Kg/m3)Particle Residence Time(s)
Min
2101001.59E-231.65E+06-5.38E+038.82e-157.96E-131.5034
4101001.70e-234.89e+04-1.58e+049.43e-157.69E-132.5745
6101001.65e-233.68e+02-2.1e+0510.2e-157.36e-133.357

At mass flow rate = 6kg/s and Diameter of pipe = 63mm with wall thickness 3mm.


Different Diameter of the tubing

At D=50mm with wall thickness 3mm

Mass Flow rate (Kg/s)Pressure(Pa)DPM erosion RateStatic Pressure (Pa)Particle Acceration RateDPM Concentration (Kg/m3)Particle Residence Time(s)
Min
2101001.39e-231.5E+06-3.8E+038.2e-159.6E-131.253
4101001.23e-238.9e+04-1.8e+044.3e-156.9E-131.5845
6101002.39e-223.8e+02-2.01e+051.2e-143.6e-132.357

Influence of Charpy test on the Al-Mn Alloy Pipe

Charpy V-Notch Test

The Charpy impact test, also known as the Charpy V-notch test, is a regulated high strain-rate test that assesses how much energy a material absorbs during fracture. The absorbed energy of a material is a measure of its notch toughness. It is frequently used during manufacturing since it is simple to set up and carry out, and results can be acquired fast and cheaply. The fact that certain outcomes are just comparative is a drawback. In the Charpy Impact Test, a notched impact specimen is struck with such a swaying weight or a “tup” attached to a swinging pendulum. When the specimen is struck, it breaks at its notched cross-section, and the upward swing of the pendulum is used to calculate the dividing the maximum load (notch toughness).

Impact test results on low- and high-strength materials

The impact energy of low-strength metals that do not alter fracture mode with heat is normally high & temperature responsive. Impact tests are not generally employed for testing the fracture resistance of low-strength materials whose fracture modes stay constant with temperature for these reasons. For low-strength materials that do vary in formation of cracks with temperature, including such body-centered cubic (BCC) metallic elements, impact tests often demonstrate a wear resistant transition.

In general, high-strength materials have low impact energies, indicating that fractures can easily initiate and propagate in these materials. Impact energies of high-strength materials other than steels or BCC transition metals are typically temperature insensitive. Because steels undergo tiny ductile-brittle transition, high-strength BCC steels exhibit a greater variance of impact energy than high-strength metals who do not have a BCC structure. Regardless, due to their brittleness, high-strength steels have a limited maximum impact energy.

Tensile testing may be used to determine a material’s toughness, since the total area under its stress-strain curve measures, at low strain rates, decrease of area and total elongation – both of which are susceptible to fracture.

The energy absorbed in the fracture of the specimen is used to estimate the impact toughness of a metal. This is accomplished behaviors by watching the height at which the pendulum is released and the height to which the pendulum swings after striking the specimen.

So after doing the fluid flow analysis on the Al-Mn alloy pipe, the impact test has also done. The charpy test has simulated on the explicit dynamics model with the help of ansys software.

Geometry

The dimension of the pipe kept the same. The side supporting members are added for the conduction of the test. Also the hammer has been pointed on the downward direction of the pipe. The size of the hammer is 30mmx35mmx10mm.

Figure 19 Geometry for the charpy test

Mesh

The total number of node and elements are 7078 and 4320.

Figure 20 Mesh of geometry

Explicit Dynamics

The hammer has been given the several velocities to test at what velocity the pipe used to get fail. So in this we began with 0.1 m/s to 10m/s. The side supports are fixed.

Figure 21 Explicit Dynamics

Solution

For the total deformation, strain and stress, plots has results.

Figure 22 Total Deformation on Pipe at 0.1m/s velocity

Figure 23 Equivalent Elastic Strain at 0.1m/s

Figure 24 Equivalent von misses stress

Table 4 showing results at various velocities

Hammer Velocity
Total DeformationEquivalent Elastic StrainEquivalent (von-Mises) Stress
0.1 m/sMinimum8.1975e-010 m7.2679e-010 m/m107.67 Pa
0.2 m/sMinimum1.0959e-007 m9.6926e-009 m/m560.65 Pa
0.5 m/sMinimum3.15e-007 m6.2327e-008 m/m12495 Pa
1 m/sMinimum6.8234e-007 m5.5925e-008 m/m1880.2 Pa
10 m/sMinimum6.3641e-006 m7.57e-007 m/m70937 Pa

Conclusion

The researcher has concluded that corrosion behavior of compounds and metals are basically influenced through their current circumstance. In the open climate, consumption gets relied upon the varieties of occasional climate. Presently, these climatic conditions can be isolated as; metropolitan, provincial, modern and marine. It is proof that erosion conduct of the metallic materials are being utilized in the biomedical applications which is of high meaning of bio-compatibility. Manganese is being known to be the alloying component of the Al amalgams which contributes up uniform deformity. In the current occasions, it has been tracked down that the manganese have with increment almost more than 0.5wt% in such the aluminum composites appear to have 6000 and 7000 series of amalgams. The researcher will be conducting the secondary research for this research.

In addition, the influence of initial filling parameters on the fluid flow, Corrosion behaviors and particles distribution have also been studied. The conclusions can be summarized as follows:

● By analyzing levels of particle concentrations, and types of flow; it was found that the erosion rate increases with the increase of flow velocities and particle concentration levels as well.

  • Complete change is observed in the erosion rate when we change the flow from laminar regime to turbulent one.

● Higher filling rate, shorter Corrosion time.

● Higher initial filling temperature, longer Corrosion time.

● Larger initial filling inlet diameter, longer Corrosion time.

● The inclusions cluster area influence by the Corrosion process.

● Discrete Random Walk Model is necessary for simulate inclusions distribution.

● Time scale of DRW model have an impact on the particles distribution.

● Inlet diameter influence particles distribution.

● The optimal sampling position inside the sampler mold can be predict by this mathematical simulation.

In the impact charpy test, at the higher velocity the pipe has got failed The stress value is. This is acceptable.

Future Work

In order to investigate more realistic results from the numerical models, a 3D model with finer mesh is suggested to be calculated for simulating the whole sampling procedure. In addition, the simulation results can be validated with physical experimental results and the assumptions and boundary conditions could be made on the basis of the physical experimental data. Furthermore, for a better understanding of the particles behaviors, more types of inclusions can be injected into the computational domain with different physical parameters.

Reference List

AZO Materials (2021) The Properties and Effects of Manganese as an Alloying Element Available at: https://www.azom.com/article.aspx?ArticleID=13027 [accessed on 19th October 2021]

Cazeaux, C., 2017. Art, research, philosophy (p. 202). Taylor & Francis.

Hossain, S., Niihori, Y., Nair, L.V., Kumar, B., Kurashige, W. and Negishi, Y., 2018. Alloy clusters: Precise synthesis and mixing effects. Accounts of chemical research51(12), pp.3114-3124.

Mohajan, H.K., 2018. Qualitative research methodology in social sciences and related subjects. Journal of Economic Development, Environment and People7(1), pp.23-48.

Nam, S.W. and Lee, D.H., 2020. The effect of Mn on the mechanical behavior of Al alloys. Metals and materials6(1), pp.13-16.

Natesan, M., Selvaraj, S., Manickam, T. and Venkatachari, G., 2008. Corrosion behavior of metals and alloys in marine-industrial environment. Science and technology of advanced materials.

Nayak, J.K. and Singh, P., 2021. Fundamentals of Research Methodology Problems and Prospects. SSDN Publishers & Distributors.

Packard, M.D., 2017. Where did interpretivism go in the theory of entrepreneurship?. Journal of Business Venturing32(5), pp.536-549.

Ryan, G., 2018. Introduction to positivism, interpretivism and critical theory. Nurse researcher25(4), pp.41-49.

Snyder, H., 2019. Literature review as a research methodology: An overview and guidelines. Journal of business research104, pp.333-339.

TWI (2021) What Is Corrosion? -Definition And Prevention Available at: https://www.twi-global.com/technical-knowledge/faqs/what-is-corrosion [accessed on 19th October 2021]

Ryungeun Song, Minki Lee, Hyeokgyun Moon, Saebom Lee, Seonghun Shin, Dohyung Kim, Yoonhyun Kim, Bukuk Oh, Jinkee Lee. (2021) Particle dynamics in drying colloidal solution using discrete particle method. Flexible and Printed Electronics 6:4, 044007.

Online publication date: 29-Dec-2021.

Jieli Wei, Huanyu Zhu, Zhixiang Zhu, Xiaomin He, Zhuyin Ren. (2021) Analysis of supersonic shear effects on flame characteristics of an evaporating flame-holder. Aerospace Science and Technology 116, 106851.

Online publication date: 1-Sep-2021.

Shanqun Chen, Runchao Tang, Longzhu Zhang, Bin Liao, Gianfranco Carotenuto. (2021) Numerical Investigation of Wind Erosion to the Grooved Concrete Wall Surface under a Wind-Blown Sand Movement. Advances in Materials Science and Engineering 2021, 1-13.

Online publication date: 19-Jan-2021.

Agusril Syamsir, Syahidatul Islamiah, Shuhairy Norhisham, Nur Liyana Mohd Kamal, Norazman Mohamad Nor, Vivi Anggraini. 2021. Investigation on Behavior of Concrete Slab Due to Low Velocity Impact Using Numerical Modeling. ICCOEE2020, 517-523.

Metals Handbook, vol. 1, p. 940, Properties and Selection, ASM (1961).

G. G. Garett and J. F. Knott,Metall. Trans. 9A, 1187 (1978).

J. S. Staner,Metall. Trans. 9A, 769 (1978).

H. Westengen, L. Auran and O. Reiso,Aluminum 57, 797 (1981).

“Sharnet”, ANSYS Fluent 6.3 User’s Guide. [online] Available at: https://www.sharcnet.ca/Software/Fluent6/html/ug/node901.htm.

T. H. Shih, W. W. Liou, A. Shabbir, Z. Yang, and J. Zhu. “A New k-ε Eddy Viscosity Model for High Reynolds Number Turbulent Flows—odel Development and Validation. Computers Fluids”. 24(3):227-238, 1995

Gray, Aluminum, 81 (2005) 197.

W.S. Miller, L. Zhuang, J. Bottema, A.J. Witterbrood, P.De Smet, A. Haszler, A.

  1. Vieregg, Mat. Sci. Eng., A280 (2000) 37.
  2. S. Frankel, J. Electrochem. Soc., 145 (1998) 2186.

L.L. Shreir, R.A. Jarman, T. Burstein, Corrosion, Volume 1: Metal/Environment Reactions, Chap. 4.1, 3rd edition, Butterworth-Heinemann (1994) ISBN: 0-750 61077-8.

R. Winston Revie, Uhlig’s Corrosion Handbook, Chap. 40, 2nd Edition, ISBN: 0- 471-78494-4.

V.S. Sinyavskii, Prot. Met., 37 (2001) 469.

R.C. Newman, Corr. Sci., 37 (1995) 527.

N. Birbilis, M.A. Easton, A.D. Sudholz, S.M. Zhu, and M.A. Gibson, On the corrosion of binary magnesiun-rare earth alloys, Corrosion Science, 51, (2009), 683-689.

G. Song and D. StJohn, The effect of zirconium grain refinement on the corrosion behavior of magnesium-rare earth alloy MEZ, Journal of Light Metals, 2, (2002), 1-16.

X. Zhang, D. Kevorkov, I.-H. Jung, and M. Pekguleryuz, Phase equilibria on the ternary Mg-Mn-Ce system at the Mg-rich corner, Journal of Alloys and Compounds, 482, (2009), 420-428.

M. Liu, P.J. Uggowitzer, P. Schmutz, and A. Atrens, Calculated phase diagrams, iron tolerance limits, and corrosion of Mg-Al alloys, Journal of Materials, 60(12), (2008).

S.L. Sin, D. Dube, and R. Tremblay, Characterisation of Al-Mn Particles in AZ91D invesment castings, Materials Characterization, 58, (2007), 989-996.

A.-J.K. J.-G. Kim, Effect of alloying elements on electrochemical properties of magnesium-based sacraficial anodes, Corrosion Science, 56(4), (2000), 380-388.

M. Pourbaix, “Atlas of Electrochemical Equilibria in Aqueous Solutions,” NACE and

Cebelcor, Houston, 1974.

E. Hatch, (ed.), Aluminum, Properties end Pltyzical Metallurgy 1984, ASM International, Materials Park, OH, 44073-0002, p. 295 (Fig. 19), p. 261 (Fig. 3), p. 303 (Fig. 27).corroalon of Aluminum and Its Alloys 46Z:s.

E. H. Hollingsworth and H. Y. Hunsicker, “Corrosion of Aluminum and Aluminum Alloys,” ASM Handbook, Vol. 13, Corrosion, 1987, ASM International, Materials Park, OH, 44073-0002, p. J92 (Fig. 11).

B. W. Lifka and D. Sprowls, Paper presented at the 7th Annual TMS-AIME Spring Meeting, Toronto, Ontario, May 19, 1975.

C. Q. Bowles and J. Schijive, “Experimental Observations of Environmental Contri- butions to Fatigue Crack Gtowth,” Corrosion Fatigue, ASTM STP 801, (T. W. Crooker and B. N. Leis, eds)., 1983, ASTM, pp. 9d-114.

K. Schulte, H. NowackG, and Liitjering, Environntenially Assisted Cracking, ASTMSTP 1049, (W. B. Lisagor, T. W. Crooked, and B. N. Lets, eds)., 1990, ASTM, pp.347 373.

R. E. Ricker and D. J. Du9uette,Met. Trans. A, l9A, July 1988, pp. 1775 1784.

H. Leth-Olsen, and K. Nisancioglu, “Filiforin Corrosion Morphologies on Painted Aluminum 3105 Coil Material,” Corrosion, 1997, 53(9), 705 717.

W. H. W. 8labaugh, S. E. Dejager, S. E. Hoover, and L. L. Hutchinson, “Filiform Corrosion of Aluminum,” 1. Paint Technol., 1972, 44, 566, pp. 76 83.

S. C. Dexter, “Localized Biological Corrosion,” ARM Handbook, Vol. 13, Corrosion, (formerly 9th Edn, Metals Handbook), ASM International, Metals Park, OH, pp. 114-122.

E. E. Murphy, “Aging Aircraft: too old to fly?” IEEE Spectrum, June 1989, 26, pp. 28 31.

S. Wernick, R. Pinner, and P. G. Sheasby, “Surface Treatment and Finishing of Alumi- num and its Alloys,” 5th Edn, Vol. 1, 1987, ASM International, Metals Park, OH.

A. Kuznetsovn, T. D. Burleigh, V. Zhukov, J. Blachere, and J. T. Yates Jr., “Electroehemical Evaluation of a New Type of Corrosion Passivation Layer: Artifici- ally Produced Al,O Films on Al,” Langmuir, 1998, 14(9), pp. 2502 2507.

R. H. Brown, “Aluminum Alloy Laminated,” in Composite Engineering Laniinaies, (A.G. H. Dietz, ed.), 1969, MtT Press.

W. Frñmberg and F. A. S. Donaldson, “Electroplating with Aluminum,” Advanced Materials & Processes, 1996, 149(2), pp. 33 35.

A. H. Roebuck, “Inhibition oL Aluminum,” in Corrosion Inhibitors (C. C. Nathan, ed.), 1973, NACE, pp. 240 244.

C. A. Witt, “Korrosion-lnhibitoren fiir Aluminium, Blei, Kupfer und Zink,” 1999, Aluminium-Verlag, Diisseldorf.

G. S. Frankel, M. A. Russak, C. V. Jahnes, M. Mirzamaani, and V. A. Brusic, “Pitting of Sputtered Aluminum Alloy Thin Films,” J. Electrochem. Soc., 1989, 136(4), pp. 1243 1244.

E. L. Colvin, L. F. Vega, M. W. Egbert, T. Nakayama, K. Ikeda, H. Shige, T. Ueda, and

M. Inman, “Filifntm Corrosion of Aluminum Auto Body Sheet in Accelerated and Outdoor Environments,” Society of Automotive Engineers, 1997, Paper 970735.

F. S. Bovard, T. D. Burleigh, and A. T. Smith, “Electrochemical Impedance SQ8CtfOScopy of Electrocoated Aluminum Food Cans,” Electrochimica Acta, 1995, 40(2), pp. 201 207.

T. D. Burleigh and A. T. Smith, “A Simple Impedance Spectra Method to Measure the Thickness of Nonporous Anodic Oxides on Aluminum,” J. Electrochemical Society, 1991, 138(8), pp. L34-35.

B. Lifka, in Corrosion Engineering Handbook (P. A. Schweitzer, ed.), 1996, Marcel Dekker, NY, p. 129.

R. B. Mears, “Aluminum and Aluminum Alloys,” in Cnrroxion Handbook (H. H. Uhlig ed.), 1948, John Wiley & Sons, Inc., NY.

Ekuma, C.E., 2006. Effects of zinc addition on the corrosion susceptibility of Al-Alloys in selected media concentration. B.Sc Thesis. EBSU, Nigeria.

Ekuma, C.E. and N.E. Idenyi, 2006. The inhibition characteristics of brine on the corrosion susceptibility of Al-Zn alloy systems. J. Applied Sci., 6: 1751-1755.
CrossRef  |  Direct Link  |  

Fontana, M.G., 1986. Corrosion Engineering. 3rd Edn., McGraw Hill Book Co., New York

Idenyi, C.E., C.E. Ekuma and I.O. Owate, 2006. The influence of alloy composition on the passivation layer characteristics of Al-Zn alloys systems. Proceedings of Materials Science and Technology 2006 Meeting and Exhibition, Oct. 15-19, Cincinnati, Ohio, USA.

 Schweitzer, P.A., 1989. Corrosion and Corrosion Protection Handbook. Marcel Dekker Inc., New York

Shreir, L.L., 1994. Corrosion Vol. 1 Metal/Environment Reactions. Corrosion Control, Butterworth Heinemann Ltd., Oxford

Meyers Marc A; Chawla Krishan Kumar (1998). Mechanical Behaviors of Materials. Prentice Hall. ISBN 978-0-13-262817-4.

The Design and Methods of Construction Of Welded Steel Merchant Vessels: Final Report of a (U.S. Navy) Board of Investigation (July 1947). “Welding Journal”. 26 (7). Welding Journal: 569.

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