Static and Thermal Analysis of Aluminium (413,390,384 and 332) Piston Using Finite Element Method

The main objective of this research was to examine the suitability of aluminium alloy to design a piston of an internal combustion engine for improvement in weight and cost reduction. The piston was modelled using Autodesk Inventor 2017 software. The modelled piston was then imported into Ansys for further analysis. Static structural and thermal analysis were carried out on the pistons of the four different materials namely: Al 413 alloy, Al 384 alloy, Al 390 alloy and Al332 alloy to determine the total deformation, equivalent Von Mises stress, maximum shear stress, and the safety factor. The results of the study revealed that, aluminium 332 alloy piston deformed less compared to the deformations of aluminium 390 alloy piston, aluminium 384 alloy piston and aluminium 413 alloy piston. The induced Von Mises stresses in the pistons of the four different materials were found to be far lower than the yield strengths of all the materials. Hence, all the selected materials including the implementing material have equal properties to withstand the maximum gas load. All the selected materials were observed to have high thermal conductivity enough to be able to withstand the operating temperature in the engine cylinders.

Effectiveness of Sodium Silicate on the Corrosion Protection of AA7075-T6 Aluminium Alloy in Sodium Chloride Solution

The influence of sodium silicate on the corrosion behaviour of aluminium alloy 7075-T6 in 0.1 M sodium chloride solution was studied by open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) techniques. Scanning electron microscopy (SEM) was used to characterize the AA7075-T6 surface. Silicate can significantly reduce corrosion deterioration and the inhibition efficiency increases with the concentration of Na2SiO3. The corrosion inhibition mechanism involves the formation of a protective film over the alloy surface by adsorption of aluminosilicate anions from solution, as has also been suggested by others in literature.

Effect of minor Zr and Sc on microstructures and mechanical properties of Al-Mg-Si-Cu-Cr-V alloys

The effects of minor contents of Zr and Sc on the microstructures and mechanical properties of Al-Mg-Si-Cu-Cr-V alloy were studied. The results show that the effects of minor Zr and Sc on the as-cast grain refinement in the ingots, the improvement in the strength of the as-extruded alloys and the restriction of high angle grain boundaries in the aged alloys can be sorted as Al3ScAl3 （Zr,Sc）Al3Zr. None of them could stop the nucleation of recrystallization, but Al3 （Zr,Sc） phase is a more effective inhibitor of dislocation movement compared to Al3 Sc in the aged alloys. Compared with the mechanical properties of the aged alloy added only 0.15% Sc, the joint addition of Zr and Sc to the alloy leads to a very slight decrease in strength with even no cost of ductility. Taking both the production cost and the little bad influence on mechanical properties into consideration, an optimal content of Zr and Sc in the Al-Mg-Si-Cu-Cr-V alloy to substitute 0.15% Sc is 0.13% Zr＋0.03% Sc.

Microstructural effects in corrosion of aluminium tube alloys

Fine gauge extruded aluminium alloy tubes can experience preferential corrosion and early failure when they are formed into ＂u-bend＂ via cold deformation. The relationship between the electrochemical reactivity and the microstructure of the bent vs straight parts of the tube was established. Investigations were carried out on two alloys containing 0.08% and 0.22% （mass fraction） of manganese. The corrosion morphology of bent tubes after immersion in salt water acetic acid test （SWAAT） solution showed the highest attack at the bent region of the high-Mn alloy. SEM characterisation of the alloys showed that each alloy has one main type of coarse intermetallic particle. However, TEM observation showed that there is a distinct difference in particle morphology between the bent and straight regions of the high-Mn tubes, the bent region revealed an additional population of 10 50 nm Mn-rich intermetallic particles, which increased both the anodic and cathodic reactivity. For the low-Mn alloy, no such effects were observed. The results suggested that cold deformation of the high-Mn tube allowed room temperature precipitation of fine Mn-rich particles, which increased the cathodic reactivity of that region by providing more cathodic sites, and increased the susceptibility to pitting by removing noble Mn from solid solution. Such an effect was not observed for the low-Mn alloy.

Electrodeposition of aluminium and aluminium-copper alloys from a room temperature ionic liquid electrolyte containing aluminium chloride and triethylamine hydrochloride

The electrodeposition of A1 and A1-Cu binary alloys on to gold substrates from a room temperature ionic liquid electrolyte containing A1C13-EtaNHC1 was studied. The electrochemical behavior of the electrolyte and the mechanism of deposition were investigated through cyclic voltammetry （CV）, and the properties of deposits obtained were assessed by scanning electron microscopy with energy dispersive X-ray spectroscopy （SEM-EDS） and X-ray diffraction （XRD）. A1 of 70μm in thickness and an A1-Cu alloy of 30μm in thickness with 8at% copper were deposited from the electrolyte. SEM images of the deposits indicate that the A1 deposit was smooth and uniform, whereas the Al-Cu deposit was nodular. The average crystalline size, as determined by XRD patterns, was found to be （30±5） and （29±5） nm, respectively, for A1 and A1-Cu alloys. Potentiodynamic polarization （Tafel plots） and electrochemical impedance spectroscopic （EIS） measurements showed that Al-Cu alloys are more corrosion resistant than Al.

Heat treatment of 7xxx series aluminium alloys—Some recent developments

The 7xxx series alloys are heat treatable wrought aluminium alloys based on the Al-Zn-Mg（-Cu） system. They are widely used in high-performance structural aerospace and transportation applications. Apart from compositional, casting and thermo-mechanical processing effects, the balance of properties is also significantly influenced by the way in which the materials are heat-treated. This paper describes the effects of homogenisation, solution treatment, quenching and ageing treatments on the evolution of the microstructure and properties of some important medium to high-strength 7xxx alloys. With a focus on recent work at Monash University, where the whole processing route from homogenisation to final ageing has been studied for thick plate products, it is reported how microstructural features such as dispersoids, coarse constituent particles, fine-scale precipitates, grain structure and grain boundary characteristics can be controlled by heat treatment to achieve improved microstructure-property combinations. In particular, the paper presents methods for dissolving unwanted coarse constituent particles by controlled high- temperature treatments, quench sensitivity evaluations based on a systematic study of continuous cooling precipitation behaviour, and ageing investigations of one-, two- and three-step ageing treatments using experimental and modelling approaches, in each case, the effects on both the microstructure and the resulting properties are discussed.

Electrochemical corrosion behaviour of stir zone of friction stir welded dissimilar joints of AA6061 aluminium-AZ31B magnesium alloys

Joining of dissimilar metals will offer many advantages in transportation sectors such as fuel consumption,weightreduction and emission reduction.However,joining of aluminium(Al)alloys with magnesium(Mg)alloys by fusion welding processis very complicated.Friction stir welding(FSW)is a feasible method to join these two dissimilar alloys.Mixing these two metalstogether in stir zone(SZ)leads to poor corrosion resistance.In this investigation,an attempt has been made to understand thecorrosion resistance of SZ of FSWed dissimilar joints of AA6061Al alloy and AZ31B Mg alloy.Potentiodynamic polarization testwas conducted by varying chloride ion concentration,pH value of the NaCl solution and exposure time.The corroded surfaces wereanalyzed using optical microscopy,scanning electron microscopy and XRD techniques.Of these three factors investigated,exposuretime is found to be the most significant factor to influence the corrosion behaviour of SZ of friction stir welded dissimilar joints ofAl/Mg alloys.

Kinetic behaviour of TiB particles in Al melt and their effect on grain refinement of aluminium alloys

Solidification experiments were carried out to investigate the kinetic behaviour of TiB2 particles in Al melt and their effect on the grain refinement of commercially-pure Al.A model was proposed to describe the kinetic behaviour of TiB2 particles during the whole process from the addition of TiB2 to the melt to the freezing of the melt.The results indicate that TiB2 particles are not stable in Al melt.They may dissolve and coarsen during the holding period and grow during the cooling period of the melt.The kinetic behaviour of TiB2 particles in the melt has a great influence on their number density and the grain refinement.Solute Ti addition can suppress the dissolution,Ostwald ripening and growth behaviours of TiB2 particles.

Influence of dispersoids on grain subdivision and texture evolution in aluminium alloys during cold rolling

Al-Mn alloys containing similar amounts of solutes but various dispersoid densities were cold rolled. The grain subdivision and micro-texture were examined by electron backscatter diffraction and orientation imaging microscopy. Macro-texture was measured by X-ray diffraction. It is found that a high density of fine dispersoids enhances the development of the copper and S textures at large strains （～3）, and also induces a higher fraction of high-angle grain boundaries. At smaller strains, the texture and high-angle grain boundaries are not evidently influenced by the density of dispersoids. It is suggested that the texture evolution, which is enhanced by dispersoid pinning effect, contributes to the grain subdivision and the formation of high-angle grain boundaries.

Conception of tooling adapted to thixoforging of high solid fraction hot-crack-sensitive aluminium alloys

Thixoforging is a type of semi-solid metal processing at high solid fraction (0.7<φs<1), which involves the processing of alloys in the semi-solid state.Tooling has to be adapted to this particular process to benefit shear thinning and thixotropic behaviour of such semi-solid material.Tooling parameters, such as the forming speed and tool temperature, have to be accurately controlled because of their influence on thermal exchanges between material flow and tool.These thermal exchanges influence the high-cracking tendency and the rheology of the semi-solid material during forming, which affects parts properties and therefore their quality.Extrusion tests show how thermal exchanges influence quality of thixoforged parts made of 7075 aluminium alloys at high solid fraction by modifying process parameters like forming speed, tool temperature and tool thermal protector.Thus an optimum in terms of thermal exchanges has to be found between surface quality and mechanical properties of the part.A direct application is the evaluation of surface quality of thixoforged thin wall parts made of 7075 aluminium alloy.

Impact of Zener-Hollomon parameter on substructure and texture evolution during thermomechanical treatment of iron-containing wrought aluminium alloys

The objective of the investigation is to evaluate the influence of the Zener-Hollomon parameter on substructure and texture evolution in iron-containing wrought aluminium alloys (type AA8011). Methods applied are X-ray texture analysis, electron backscatter diffraction (EBSD) and optical microscopy. The results show a serious impact of the Zener-Hollomon parameter on cube texture evolution during the thermomechanical treatment in iron-containing aluminium alloys. An increase in the Zener-Hollomon parameter reduces the survivability of cube texture during hot deformation and reinforces particle-stimulated nucleation (PSN) during the annealing process. However, thermomechanical treatment at low temperatures leads to active precipitation and as a result fine-dispersed participles tend to block all nuclei except for those producing large cube-oriented grains. It is concluded that in iron-containing wrought aluminium alloys, the general correlation between the Zener-Hollomon parameter and subgrain size is similar to that observed in 3xxx series alloys and can be described by the specific set of equations derived.

Corrosion pathways in aluminium alloys

The corrosion pathways in AA2024-T3, AA5083-O and AA6082-T6 alloys have been investigated. The objective of the investigation is to further the understanding of the complex localised corrosion mechanism in aluminium alloys. The investigation was carried out by examining the corroded surfaces of the alloys after potentiodynamic polarization tests in a 3.5% NaCl solution with the aid of a scanning electron microscope, and by analysing the flow of anolyte solution using the scanning vibrating electrode technique. The results revealed that the overall corrosion pathways in the alloys are distinctively different and are influenced by the flow of anolyte solution. Also revealed, was the fact that corrosion propagates in two ways （particularly in the AA5083-O and AA6082-T6 alloys）： an overall pathway in the corrosion front （filiform-like pathway in the AA5083 alloy and organized linear pathways in AA6082 alloy）; and the crystallographic channelling along the （100） directions. These are dependent on the grain distinct features of the AA5083-O and AA6082-T6 alloys and are not influenced by the presence of coarse second phase particles in these alloys, compared with the AA2024-T3 alloy, where the corrosion pathways are more dependent on the presence of second phase particles and grain boundary character.

Study on Grain Refining and Metamorphism of ZL111 Aluminium Alloys

Vacuum sintering and ball milling methods were employed in the preparation process of Ti-C grain refine- ment and the ability of refiners with varying ratios of Ti and C to refine ZL111 crystal grains was tested. The refinement effect of the Ti-C ratios on tensile strength, elongation percentage, Brinell hardness, pro-eutectoid αAl and the size of the Si phase of ZL111, after modification by rare-earth and strontium nitrate, were studied by means of metallographic examination, SEM and mechanical property tests. The results show that there is an obvious increase in the tensile strength and elongation percentage of refined ZL111 with these new Ti and C refiner compounding powders, while Brinell hardness remained more or less constant. The pro-eutectoid αAl is considerably reduced in size and the Si phase shows a finer and rounder structure. The refiner exhibits a good grain refining performance when the Ti-C ratio is 25:1, for Al crystals can favorably easily form nuclei and grow up along the TiC surface thanks to the TiAl3 generated by sur- plus Ti and Al. The mechanical properties have clearly been improved by the addition of strontium nitrate to ZL111. The effective factors in the modification of mechanical properties of ZL111 are in order of importance: strontium nitrate, Ti-C ratio and rare earth.

Influence of T6 heat treatment on A356 and A380 aluminium alloys manufactured by thixoforging combined with low superheat casting

The effects of T6 heat treatment on thixoforged A356 and A380 aluminium alloys were studied.Low superheat casting(LSC)technique was carried out to prepare proper specimens for thixoforging process.The samples were poured at 20°C above their liquidus temperatures which provided the formation of equiaxed grains instead of dendritic growth.Produced billets were reheated for varied time from 20 to 80 min and thixoforged with 50%deformation rate.After thixoforging process,the samples were T6 heat treated for both A356 and A380 alloys.The microstructural evaluation and hardness alteration of thixoforged,solution treated and aged specimens were examined comparatively by using optical microscopy,scanning electron microscopy with energy-dispersive X-ray spectroscopy and Brinell hardness equipment.T6 heat treatment provided relatively uniform microstructure with newly formed precipitates that are Mg2Si and Al2Cu for A356 and A380 billets,respectively.Accordingly,hardness after artificial aging was increased considerably and reached HB 93 for A356 and HB 120 for A380 alloys.

Experimental investigation on friction stir welding of 2A12 aluminium alloys

Friction stir welding experiments were conducted to study the effects of the process parameters on the weld quality of 2A12 aluminium alloys. Through appropriate selection of the shoulder press amount （axial force）, tool rotation speed and welding speed, good joints were obtained for the test pieces with thickness of 6 ram. The microstructures in weld nugget zone, thermo-mechanical affected zone and heat-affected zone were analyzed. It is found that the ratio of the tool rotation speed to the welding speed should be optimized for a suitable shoulder press amount.

Growth restriction effects during solidification of aluminium alloys

The effects of solute elements during solidification on the grain size are very important and can be quantified by the growth-restriction parameter Q,and Q possesses the better correlation with the grain size. Based on the constitutional undercooling generated by the growth of an adjacent grain during the initial solidification,the growth-restriction parameter Q is deduced and a comprehensive physical basis of Q is obtained by using an initial solute distributing equation. For the alloys with more potent nucleants,Q is a suitable predictor of the grain size. For less potent nucleants,the relative grain size(RGS) is a more accurate prediction of the grain size. This prediction coincides with the experimental behaviors for Al-Ti and Al-Cu alloys with lower solute content.

Correlating oriented grain number density of recrystallisation in particle-containing aluminium alloys

The recrystallized grain structure of Al-（Mn）-Fe-Si alloys after isothermal annealing was studied by electron backscatter diffraction（EBSD） technique. Statistical correlation suggests that the frequency of forming P-oriented（{011}？566？） grains at a particle larger than the critical diameter（about 1.1 μm） is about 2% when the effect of fine dispersoids and concurrent precipitation is negligible. The overall grain number density is correlated linearly with the number densities of P and Cube（{001}？100？） grains. The grain number densities of typical orientations（P, ND-rotated cube {001}？310？ and Cube） and the overall recrystallized grains increase as rolling strain increases, following a similar exponential law.

Effect of united refining and modification on mechanical properties of A356 aluminium alloys

The refining and modification effect of Ti (from GRAI), B, Sr and RE (cerium-riched mixtures of rare earth) on the mechanical properties of A356 aluminum alloys under T5 and T6 treatment condition were studied by OM, SEM, EDAX, etc. It is found that the addition of RE to A356 alloys containing Ti and/or B and Sr makes strength and elongation increase in T6 treatment, but make elongation decrease in T5 treatment, at the same time, the long axis ofα(Al) grain structure decreases and the mean diameters of silicon particles increase with RE additions increasing. Grain refining with 0.01%Ti plus 0.03% B makes the dendriteα(Al) grain structure transform into equiaxed structure, resulting in obvious increase of elongation percentage. The mean diameters of silicon particles in T5 treatment are smaller than that in T6 treatment. Roundness of silicon particles in T5 treatment is higher than that in T6 treatment. A356 alloys modified and refined with Ti, B and Sr obtain the best mechanical properties in T5 treatment, however, the alloys with Ti, B, RE and Sr additions obtain the best mechanical properties in T6 treatment.

Strength properties examination of high zinc aluminium alloys inoculated with Ti addition

This paper includes studies on the influence of grain refinement treatment with respect to the composition and structure of high zinc aluminium casting alloys on the changes of their tensile properties. The Al-20 wt.%Zn alloy was inoculated with master alloys Al Ti5B1 and Al Ti3C0.15 to determine the impact of a variable titanium addition on the tensile properties of Al Zn20 alloy, and determine on this basis an optimal addition of Ti that would ensure the improvement of elongation of alloys cast in the sand mould, at the same time maintaining high tensile strength. Within the studies, light microscopy(LM) and strength tests were applied. Experimental results showed that the inoculation of high zinc aluminium alloy Al Zn20 with the master alloys Al Ti5B1 and Al Ti3C0.15 causes intensive structure refinement, while the intensity of reaction of both master alloys is comparable. The Al Ti3C0.15 master alloy addition, selected for further studies, introducing about 100 ppm Ti, enhances the tensile properties of the alloy; the elongation increases about 20% and tensile strength increases about 10% against the initial values(uninoculated alloy). Further increase of the Ti addition up to 500–600 ppm leads to the "overinoculation" effect that is accompanied by the decrease of elongation. Therefore,the Ti addition should be reduced to the level of about 100 ppm which ensures obtaining a set of optimal properties.

Effects of Cerium on Texture and Mechanical Property of 2090 Aluminium-Lithium Alloys

In order to investigate the effects of Ce on mechanical anisotorpy of Al-Li alloys, the texture of 2090 AlLi alloy with different Ce content was determined using orientation distribution function technique, in which the mechanical properties with different angles to rolling direction were measured. The effects of Ce on texture and mechanical properties of 2090 alloys were discussed. The results show that the type of main texture of 2090 alloys is {225} <554>. Ce will not change the type of main texture of the alloy, but make the distributiodn of main texture scattered. Ce can change the volume fractions of ideal texture components and will decrease the anisotropy of yield strength, hence the content of the texture components that enhance the anisotropy of yield strength can be reduced.