Aluminum Alloy Composites Research Articles

Effect of Copper Alloying and Reinforcement Percentage on the Microstructure-Tribological Aspects of the Aluminium Alloy Composites

In this study, microstructural and tribological analysis of Aluminium Alloy composites 2024 and 2900 is done. The composite with reinforcements SiC and Al2O3 from 0-20 wt% is prepared by powder metallurgy process. As microwave sintering is the process used the core is much denser than at the surface. Strength of aluminium is increased by percentage of copper alloyed in aluminium matrix. Microstructure of the sample is examined thoroughly using scanning electron microscope. X-ray diffraction patterns are investigated for the elements present in the composites and a detailed check for the intermetallic precipitates and the impurities. A uniform microstructure is obtained by microwave sintering process. Aluminium alloy 2024 and 2900 which is microwave sintered is having round-edged porosities with high ductility and toughness. Tribological studies are carried out using pin on disc wear testing machine. The results indicated that 2900 exhibited excellent frictional coefficient behavior compared to AA 2024.

High-velocity impact deformation and perforation of fibre metal laminates

The quasi-static flexural and impact performance, up to projectile impact velocities of about 270 m s−1, of fibre metal laminates (FMLs), which consist of relatively thin, alternately stacked, layers of an aluminium alloy and a thermoset glass fibre epoxy composite, have been investigated. The effects of varying (a) the yield strength, tensile strength and ductility of the aluminium alloy layer, (b) the surface treatment used for the aluminium alloy layers and (c) the number of layers present in the FML have been studied. It was found that increasing the strength of the aluminium alloy increases the quasi-static flexural strength of the FML, providing that good adhesion is achieved between the metal and the composite layers. Further, increasing the number of alternating layers of the aluminium alloy and fibre composite also somewhat increases the quasi-static flexural properties of the FML. In contrast, increasing the strength of the aluminium alloy had relatively little effect on the impact perforation resistance of the FML, but increasing the number of alternating layers of aluminium alloy and fibre composite did significantly increase the impact perforation resistance of the FML. The degree of adhesion achieved between the layers had only a negligible influence on the impact perforation resistance.

Effect of Copper Coating and Reinforcement Orientation on Mechanical Properties of LM6 Aluminium Alloy Composites Reinforced with Steel Mesh by Squeeze Casting

Uncoated and copper coated steel wire mesh reinforcing LM6 aluminium alloy composites have been produced using squeeze casting process by varying reinforcement orientation viz., 0°, 45° and 90° respectively. Microstructure of the castings has been examined and mechanical properties such as hardness, tensile strength and ductility have been investigated. Fracture surface of tensile specimens has been analysed using field emission scanning electron microscope. Microstructure of samples reveals that copper coating on steel wires improves the interface bonding between matrix and reinforcement. Average hardness values of 259 and 90 Hv have been observed in steel wire and matrix respectively. Tensile strength of composites increases with increasing angle of reinforcement orientation from 0° to 90°. Tensile strength increases up to 11% by reinforcing copper coated steel wire mesh at 90° orientation as compared to LM6 aluminium alloy. Fracture surface of composites shows pullout of steel wires in uncoated steel wire mesh composites and broken wires in copper coated steel wire mesh composites respectively. Dimples have been observed on the fracture surface of LM6 aluminium alloy. In general, copper coated steel wire mesh composites offer better hardness and tensile strength compared to uncoated steel wire mesh composites and LM6 aluminium alloy. This may be attributed to the copper coating on steel wires which results better interface bonding between matrix and reinforcement.

Ballistic impact velocity response of carbon fibre reinforced aluminium alloy laminates for aero-engine

Aerospace and other industries use fibre metal laminate composites extensively due to their high specific strength, stiffness and fire resistance, in addition to their capability to be tailored into different forms for specific purposes. The behaviours of such composites under impact loading is another factor to be considered due to the impacts that occur in take-off, landing, during maintenance and operations. The aim of the study is to determine the specific perforation energy and impact strength of the fibre metal laminates of different layering pattern of carbon fibre reinforced aluminium alloy and hybrid laminate composites of carbon fibre and natural fibres (kenaf and flax). The composites are fabricated using the hand lay-up method in a mould with high bonding polymer matrix and compressed by a compression machine, cured at room temperature for one day and post cure in an oven for three hours. The impact tests are conducted using a gun tunnel system with a flat cylindrical bullet fired using a helium gas at a distance of 14 inches to the target. Impact and residual velocity of the projectile are recorded by high speed video camera. Specific perforation energy of carbon fibre reinforced aluminium alloy (CF+AA) for both before and after fire test are higher than the specific perforation energy of the other composites considered before and after fire test respectively. CF +AA before fire test is 55.18% greater than after. The same thing applies to impact strength of the composites where CF +AA before the fire test has the highest percentage of 11.7%, 50.0% and 32.98% as respectively compared to carbon fibre reinforced aluminium alloy (CARALL), carbon fibre reinforced flax aluminium alloy (CAFRALL) and carbon fibre reinforced kenaf aluminium alloy (CAKRALL), and likewise for the composites after fire test. The considered composites in this test can be used in the designated fire zone of an aircraft engine to protect external debris from penetrating the engine shield due to higher values of impact strength and specific perforation energy as highlighted by the test results.

Garnet and Al-flyash composite under dry sliding conditions

The dry sliding wear behaviour of LM 24 aluminum alloy composites reinforced with garnet particles was evaluated. Stir casting technique was used to fabricate the composites. A pin-on-disc wear-testing machine was used to evaluate the wear rate, in which an EN 24 steel disc was used as the counterface. Results indicated that the wear rates of the composites were lower than that of the matrix alloy and further decreased with the increase in garnet content. However, in both unreinforced and reinforced composites, the wear rate increased with the increase in load and the sliding speed. Increase in the applied load increased the wear severity by changing the wear mechanism from abrasion to particle cracking-induced delamination wear. It was found that with the increase in garnet content, the wear resistance increased monotonically. The observations have been explained using scanning electron microscopy analysis of the worn surfaces and the subsurface of the composites. In this work, the most influencing input and output parameters have been performed and the process parameters have been prioritized using genetic algorithm. Genetic algorithm is used to optimize the most influencing input as well as output process parameters. The practical significance of applying genetic algorithm to dry sliding wear behavior process has been validated by means of computing the deviation between predicted and experimentally obtained wear behavior of metal matrix composite.

Optimization of Stir Casting Process Parameters to Improve the Hardness Property of Al/RHA Matrix Composites

The development of inexpensive materials reinforced metal matrix composites has become an important area of research interest in Material Science and its growing rapidly in various engineering fields. Therefore, the need for optimization becomes necessary in developing a composite material when different process parameters are to be used simultaneously. This is an efficient method to design a metal matrix composite with reliable and predictable mechanical properties which will be highly beneficial to the manufacturing industry. The application of trial and error method for the design of process parameters is found to be highly costly, time consuming and difficult to achieve desired products with optimum properties. In this study, composites of aluminium alloy reinforced with locally available inexpensive rice husk ash (RHA) was developed by stir casting method. In the manufacturing of the composites of Al/RHA, a three factor historical data (HD) model was used to design the experiment. The factors considered are weight fraction (5%, 10% and 15%), particle size (150 µm, 300 µm and 600 µm) and stirring time (10 mins, 20 mins and 30 mins) at stirring speed of 140 rpm, while hardness is the major response. Response surface methodology was used in this study to investigate the effect of the casting parameters for the performance of the Al/RHA composites. The Vickers hardness test was performed on the composite specimens. The hardness test revealed that the particle size, weight fraction and stirring time have their effect on the hardness of the composite. Highest hardness was obtained at 150 µm particle size, 15% weight fraction and stirring time of 30 mins. This study attempts to establish the trend between processing parameters with hardness of composite.

Optimization of Stir Casting Process Parameters to Improve the Hardness Property of Al/RHA Matrix Composites

The development of inexpensive materials reinforced metal matrix composites has become an important area of research interest in Material Science and its growing rapidly in various engineering fields. Therefore, the need for optimization becomes necessary in developing a composite material when different process parameters are to be used simultaneously. This is an efficient method to design a metal matrix composite with reliable and predictable mechanical properties which will be highly beneficial to the manufacturing industry. The application of trial and error method for the design of process parameters is found to be highly costly, time consuming and difficult to achieve desired products with optimum properties. In this study, composites of aluminium alloy reinforced with locally available inexpensive rice husk ash (RHA) was developed by stir casting method. In the manufacturing of the composites of Al/RHA, a three factor historical data (HD) model was used to design the experiment. The factors considered are weight fraction (5%, 10% and 15%), particle size (150 µm, 300 µm and 600 µm) and stirring time (10 mins, 20 mins and 30 mins) at stirring speed of 140 rpm, while hardness is the major response. Response surface methodology was used in this study to investigate the effect of the casting parameters for the performance of the Al/RHA composites. The Vickers hardness test was performed on the composite specimens. The hardness test revealed that the particle size, weight fraction and stirring time have their effect on the hardness of the composite. Highest hardness was obtained at 150 µm particle size, 15% weight fraction and stirring time of 30 mins. This study attempts to establish the trend between processing parameters with hardness of composite.

Mechanical and Life Properties of Sheets from Alloys of the Al – Mg – Sc System

The characteristics of strength, static crack resistance, rate of growth of fatigue cracks and cyclic endurance of annealed sheets from weldable alloys of the Al – Mg – Sc system are studied as compared to annealed sheets from alloy AMg6. The compositions of aluminum alloys with scandium (01545 and 1570S) with characteristics substantially superior to those of AMg6 and level of properties comparable to that of the base aircraft not weldable alloy 1163 in state T6 are determined.

The Mechanical Properties of an Aluminium Composite with Different Carbon Fibre Content

Short modified carbon fibres (Cf) were applied to reinforce a 2024 aluminium alloy to investigate the effect of Cf content on the mechanical properties of an aluminium matrix composite. As Cf volume fraction increased, the composite had more pores and defects while Cf were distributed uniformly throughout and combined well with the matrix. Hot extrusion reduced pore and defect frequency, and made Cf aligned in the extruded direction. These factors, such as Cf volume fraction, distribution, interface combination with the matrix, pores and defects mainly induced by Cf adding, had a great influence on the mechanical properties of such aluminium matrix composites. In comparison with the matrix material, the elastic properties of the prepared composite were improved while its plasticity decreased. The results show that Cf surface modification, component control, and optimum heat treatment should be investigated further to improve the property of short Cf reinforced aluminium alloy composites.

Evaluation of Mechanical Properties of Aluminum Alloy (Al2024) Reinforced with Silicon Carbide (SiC) Metal Matrix Composites

The investigation of mechanical properties of silicon carbide (SiC) powders reinforced with aluminum alloy composites are recorded in this paper. SiC powders of approximately 35µm size were added in an aluminum alloy matrix to manufacture the samples of ratios 1, 2, 3 and 4 by weight % using the stir casting technique. The specimens were fabricated and several tests were conducted to evaluate the mechanical properties such as tensile strength, hardness and impact strength and then the values are compared with the base alloy. It has been observed from the results that the hardness, impact energy and tensile strength increases with the increase in % of SiC particles until 2% and drops on further increase in the SiC particles.

Tribological Properties of Aluminium Alloy Composites Reinforced with Multi-Layer Graphene—The Influence of Spark Plasma Texturing Process

Self-lubricating composites are designed to obtain materials that reduce energy consumption, improve heat dissipation between moving bodies, and eliminate the need for external lubricants. The use of a solid lubricant in bulk composite material always involves a significant reduction in its mechanical properties, which is usually not an optimal solution. The growing interest in multilayer graphene (MLG), characterised by interesting properties as a component of composites, encouraged the authors to use it as an alternative solid lubricant in aluminium matrix composites instead of graphite. Aluminium alloy 6061 matrix composite reinforced with 2–15 vol % of MLG were synthesised by the spark plasma sintering process (SPS) and its modification, spark plasma texturing (SPT), involving deformation of the pre-sintered body in a larger diameter matrix. It was found that the application of the SPT method improves the density and hardness of the composites, resulting in improved tribological properties, particularly in the higher load regime.

Electrodeposition of aluminum and aluminum-magnesium alloys from organic solvent system

Aluminum and aluminum-magnesium alloys were prepared by direct current electro-deposition and pulse electro-deposition in AlCl3-LiAlH4-benzene-tetrahydrofuran (THF) system. Electrochemistry experiment was conducted by three electrode system and analyzed by Chronoamperometic plots. The surface morphology, composition and content of aluminum and aluminum magnesium alloys were studied by scanning electron microscope (SEM) and energy spectrum (EDS). The results show that the coatings of aluminum and aluminum magnesium are superior when the pulse duration ratio (ton:toff) is 0.08s:0.02s. The coatings are best when DC deposition current density in 14.89mA/cm2. SEM shows that by DC deposition the grain sizes are thick and the surface is rough. But the coatings obtained by pulse electro-deposition are more uniform, thinner and the surface is flatter than obtained by DC deposition.

Simulation of Stress Field in High-Frequency Welded Pipe of Composite Aluminum Alloy

Based on the finite element model of high frequency welded pipe welded of composite aluminum alloy, the stress-time variation curves of welded pipe in different welding parameters were obtained. The analysis shows that the residual tensile stress in the weld zone is largest. At the same time, the weld tensile test and hydrostatic burst test were conducted. When the residual tensile stress in the weld zone is high, the blasting pressure which the weld can withstand is small, and the cracking position is often in the welded seam zone. To a certain extent, the change of the thermal stress in the welding process and the residual stress in the cooling process can be accurately reflected by the finite element analysis method.

Manufacturing of AA2124 Aluminum Alloy Metal Matrix Composites Reinforced by Silicon Carbide Processed by Powder Metallurgy Techniques of High Energy Ball Milling and Hot Extrusion

Aluminum alloy metal matrix composites are a class of materials object of large and intensive research during the last years. In this study an AA2124 aluminum alloy were processed by means of mechanical alloying added by 10, 20 and 20 percent of silicon carbide (SiC) in vibratory SPEX type mill during 60 and 120 minutes. After this the composites powders obtained were characterized by means of Scanning Electron Microscopy (SEM) plus Energy Dispersive Spectroscopy (EDS) to determine the powders morphology. In order to consolidate the AA2124 aluminum alloy composites reinforced by silicon carbide (SiC) composites, the powders processed by high energy ball milling technique were hot extruded and the billets were characterized by SEM to determine the microstructure and the distribution of the reinforced ceramic phase of silicon carbide throughout the aluminum matrix and at last the microhardiness Vickers technique were used to evaluate the mechanical properties.

Effect of Multiwall Carbon Nanotubes (MWCNs) Reinforcement on the Mechanical Behavior of Synthesis 7075 Aluminum Alloy Composites by Mechanical Milling

Effect of Multiwall Carbon Nanotubes (MWCNs) Reinforcement on the Mechanical Behavior of Synthesis 7075 Aluminum Alloy Composites by Mechanical Milling

Micro structural characteristics and mechanical behaviour of aluminium matrix composites reinforced with titanium carbide

In this study titanium carbide particles reinforced in aluminium alloy (A 6063) composites were fabricated successfully using stir casting method. Titanium carbide was added in 2, 4, 6, 8 and 10 percentages by weight in the aluminium alloy. Density, hardness, impact and tensile tests were conducted to assess the mechanical properties of composites. Scanning electron microscopy and X-ray diffraction techniques were employed to study the fracture mechanism and phase identification respectively. Increase in addition of titanium carbide decreased the impact strength and elongation of composites to a maximum of 31% and 35% respectively. The density, hardness and tensile strength of composites increased to a maximum of 7.8%, 20% and 19.55 respectively while adding titanium carbide particles. X-ray diffraction results indicated that Al and TiC were the principal elements in composites and are free from intermetallics. Microstructures of the fractured composite specimen are characterized by ridges, voids, cracks, dimples, particle fracture and ridges.

The Simulation of Temperature Field in Induction Welding of Composite Aluminum Alloy Thin-Walled Tube

Welding temperature is the main factor that influences the welding quality in the high frequency induction welding of composite aluminum alloy thin-walled tubes. The finite element analysis software ANSYS was used to simulate the temperature field. One complete penetration of thin-walled tube and boundary conditions of convection and radiation as well as latent heat phase change were taken into account. Then a linear heat source is used to load and calculate the temperature distribution and to draw thermal cycle curves of welding process. Research results of the temperature filed also provided the corresponding basis for further analysis of welding stress and strain.

Dry sliding wear behavior of AA6061 aluminum alloy composites reinforced rice husk ash particulates produced using compocasting

This work concentrates on the preparation of AA6061/(0, 2, 4, 6, 8 wt.%) rice husk ash (RHA) aluminum matrix composites (AMCs) using compocasting and investigation of the dry sliding wear behavior by means of pin-on-disc apparatus at room temperature. The microstructures of the composites were studied using scanning electron microscopy and electron back scattered diffraction. The micrographs confirmed successful incorporation of RHA particles into the aluminum matrix. A proper distribution of RHA particles without segregation was achieved. RHA particles refined the grains of the aluminum matrix and improved the wear resistance of the composite. The influence of RHA particulate content and applied load on the worn surface and wear debris was further reported. RHA particles improved the wear resistance of the composites and reduced the damage on the worn surface. The wear mode changed with increase in the content of RHA particles and the applied load.

Investigation of nickel metal powder on tribological and mechanical properties of Al-7075 alloy composites for gear materials

ABSTRACTThis research paper describes the fabrication of different weight percentages of (0–2 wt-%) nickel powder-filled aluminium alloy composites by stir casting techniques under a controlled environment. The physical, mechanical and tribological analyses of the nickel powder-filled aluminium alloy (Al-7075 series) composites are studied experimentally. The void content, Vickers hardness, compressive strength and impact strength of the unfilled and particulate-filled alloy composites are increased with the increase in filler content, while flexural strength of the composites shows reverse in trend. At the end, sliding wear analysis is performed to assess the wear performance of the unfilled and particulate-filled alloy composites. It is also observed that 2 wt-% nickel powder-filled alloy composite exhibits higher wear resistance as compared to other alloy composites. Finally, the microstructure analysis of the worn out composites is observed through scanning electron microscope to comprehend the wear mechanism of the composites for gear material application.

Phase Composition and Hardening of Castable Al – Ca – Ni – Sc Alloys Containing 0.3% Sc

The phase composition of aluminum alloys of the Al – Ca – Ni – Sc system containing 0.3 wt.% Sc is studied. It is shown that the aluminum solid solution may be in equilibrium not only with binary phases (Al4Ca, Al3Sc and Al3Ni) but also with a ternary Al9NiCa compound. The temperature of attainment of maximum hardening due to precipitation of nanoparticles of phase Al3Sc is determined for all the alloys studied. Principal possibility of creation of castable alloys based on an (Al) + Al4Ca + Al9NiCa eutectic, the hardening heat treatment of which does not require quenching, is substantiated.