Properties Of Aluminum Matrix Research Articles

Phase, microstructure and tensile strength of Al–Al2O3–C hybrid metal matrix composites

The aim of the present study is to investigate the effect of alumina (Al2O3)–carbon (C) reinforcement on the properties of aluminium matrix. Aluminium matrix reinforced with Al2O3–carbon (2.5, 5, 7.5 and 10 wt.%) in equal proportion was prepared by stir casting. Phase, microstructure, EDS, density, hardness, impact strength and tensile strength of prepared samples have been investigated. X-ray diffraction reports the intermediate phase formation between the matrix and reinforcement phase due to interfacial bonding between them. Scanning electron microscopy shows that Al matrix has uniform distribution of reinforcement particles, i.e. Al2O3 and carbon. Density decreases due to variation of reinforcement because ceramic reinforcement has low density. Hardness decreases due to variation of carbon since it has soft nature. Impact strength was found to increase with addition of reinforcement. Hybrid composite of Al and 5% Al2O3 + 5% carbon reinforcement has maximum engineering and true ultimate tensile strength. It is expected that the present hybrid metal matrix composites will be useful for fabricating stock screws.

Structural and mechanical characterization of stir cast Al–Al2O3–TiO2 hybrid metal matrix composites

The present paper reports the effect of aluminium oxide and titanium oxide reinforcement on the properties of aluminium matrix. Aluminium matrix reinforced with aluminium oxide–titanium oxide (2.5, 5.0, 7.5 and 10 wt.%) in equal proportion were prepared by stir casting. Phase, microstructure, energy dispersive spectroscopy, density, hardness, impact strength and tensile strength of prepared samples have been investigated. X-ray diffraction reports the intermediate phase formation between the matrix and reinforcement phases due to interfacial bonding between them. Scanning electron microscopy shows that aluminium matrix has uniform distribution of reinforcement particle i.e. aluminium oxide and titanium oxide. Density of composite decreases due to variation of reinforcement and it shows low density after preheating. Hardness decreases due to the amalgamation of reinforcements. Impact strength was found to increase with the addition of reinforcements. Hybrid composite of aluminium matrix and (5% aluminium oxide + 5% titanium oxide) reinforcements have maximum engineering and true ultimate tensile strength. It is expected that the present hybrid metal matrix composites will be useful for aircraft rivets.

Effect of Temperature Change on the Elastic Properties of Al Matrix Reinforced by Single-Walled Carbon Nanotubes

In this paper, finite element modeling is used to compute the elastic properties of aluminum matrix reinforced by carbon nanotubes at different temperatures. Different patterns, including longitudinal dispersion along the loading, longitudinal dispersion perpendicular to the loading and random dispersion, are employed to disperse the nanotubes in Al matrix. Besides, the dependence of the mechanical properties of nanotube/Al nanocomposites on the nanotube aspect ratio (the ratio of nanotube length to its diameter) and volume percentage is studied. It is shown that the effect of temperature variation on the elastic properties of nanotube/Al nanocomposites is the same as the pure Al matrix. Investigating the influence of nanotube volume percentage, it is seen that nanocomposites with larger nanotube volume percentages possess higher elastic modulus.

Experimental study of tribological and mechanical properties of aluminum matrix reinforced by Al2O3/CNTs

In recent years, since the discovery of Nano-additives especially carbon nanotubes (CNTs) and graphene, many interesting articles on composites with CNTs have been studied. CNTs have attracted considerable interest in all fields of science because of its unique characteristics. In this study, aluminum (Al) matrix reinforcement by the different volume fraction of Al2O3 and CNTs composites have been manufactured by using a powder metallurgy technique. The effects of tribological behaviors, density, hardness, and compression strength behavior of aluminum matrix Nano-composite were investigated before and after Hot Isostatic pressing (HIP). Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM) were employed to check the CNTs and hybrid composites. Results show that the density of nanocomposites decreased by 38% but after HIP, the density decreased by 45%. In addition, the hardness enhanced by 40% but, after HIP the hardness became 67%. On the other side, the compressive strength enhanced by 38% and 60% before and after HIP respectively. The coefficient of friction of nanocomposites are improved by 39%, 48% with HIP and without HIP while the wear rates improved by the addition of Al2O3 and CNTs at all volume fraction by 20%, but after HIP the enhancement became 45% at all volume concentration.

Synthesis and mechanical characterization of aluminum based hybrid nano composites reinforced with nano tungsten carbide and nano tantalum niobium carbide particles

Metal matrix nanocomposites are potential light weight engineering materials. Nano-sized reinforcements enhance the properties of aluminium matrix compared to micro-sized reinforcements. Hybrid nano reinforcement exhibit superior properties to Al matrix composites as compared with Al matrix with single reinforcement. Aluminium LM alloys give useful matrix properties as compared with other Al alloy. The present investigation aims to synthesis and characterises the aluminium LM4 alloy matrix reinforced with nano tungsten carbide (WC) and nano tantalum niobium carbide (Ta/NbC) particles. The composites were prepared by powder metallurgy technique followed by compaction and sintering process. The reinforcement ratio varies from 0.5, 1, 1.5 and 2 wt% of WC and Ta/NbC particles. The micro-structural observations were carried out using X-ray diffraction (XRD) analysis and scanning electron microscope (SEM). Mechanical properties such as micro-hardness and density of the composites were investigated. On comparison with base alloy, results indicate that increasing weight percentage of reinforcement results in an improvement of 65.4% and 79.2% in micro-hardness for single and hybrid reinforcement composites respectively. Also, it has been observed that an increase in density of the composites as compared with base alloy.

Investigation of the mechanical properties of Aluminium matrix composite for marine structures

Mechanical properties and microstructure of aluminium matrix composite was studied for application in marine environments. Composite materials based on Al-Mg alloy matrix are used for marine structures where strength to weight ratio and corrosion resistance are key requirements. Six different samples were prepared with varying amount of SiCp reinforcement from 0% to 25% at interval of 5%. The SEM/EDX and XRF analyses of the materials have shown that the materials developed contained the required elements and the reinforcement is well distributed within the alloy matrix. Highest hardness value of 75.4 HRB was obtained on the sample with 10% SiCp compared with the Al-Mg matrix. Impact energy of 18.98 J was obtained on sample with 15%SiCp which is also better compared to 9.97J as observed on the matrix alloy. The hardness and impact energy of the produced composite materials tested were found to be better than that of the control alloy sample at room temperature in all the percentages of reinforcements used for the research.Keywords: Microstructure; Silicon carbide; Metal matrix composites; impact energy

Hot Deformation Behaviors and Microstructure Evolution of SiCp/Al Composites

In order to explore the compressive properties of aluminium matrix composite reinforced with middle content SiC particles, hot compression behavior of 30%SiCp/2024A1 composite was investigated using Gleeble-1500 system at a temperatures range from 350 to 500°C and strain rates from 0.01 to 10 s−1. The associated structural changes were studied by OM, SEM and TEM observations. The results show that the true stress–true strain curves exhibited a peak stress at a small strain (<0.1), after which the flow stresses decreased monotonically until high strains, showing a dynamic flow softening. The stress level decreased with increasing deformation temperature and decreasing strain rate, indicating that the composite is a positive strain rate sensitive material. And therefore there will be a enough time for dynamic recrystallization to complete nucleation and growth at low strain rate and high deformation temperatures.

Experimental investigation of aluminum matrix functionally graded material: Microstructural and hardness analyses, fretting, fatigue, and mechanical properties

This study investigated the mechanical properties of aluminum matrix functionally graded material (FGM) reinforced by integration of aluminum 2014 alloy (AlCu4SiMg) and 15 vol% SiC. The specimens were obtained by centrifugal casting technique, followed by aging treatment. The variations that occurred in microstructure, hardness, Young’s modulus, tensile strength, yield strength, elongation, fatigue, and fretting fatigue behaviors were analyzed. In both cast and aged conditions, it was observed that hardness values and mechanical properties changed between SiC-rich and aluminum-rich regions. Fatigue and fretting fatigue data were similar. It was determined that greater wear was occurring on the pad surfaces compared to that occurring on the sample surfaces.

The Effect of Matrix on the Mechanical Properties of Squeeze Cast Al - 50 % SiC<sub>p</sub> Composites

This study has been conducted to investigate the mechanical properties of aluminum matrix 50 vol.% SiC particle (SiCp) reinforced composites produced by a squeeze casting technique. Commercial 2618, 6082, and 7012 aluminum alloys were utilized as the matrix material. Composites were tested in as-cast and T6-tempered states. Mechanical properties of the composites were determined by hardness measurements and impact tests. As-cast composites exhibited lower hardness along with a better impact resistance than their T6-tempered states. After T6-tempering the hardness of 7012 matrix composite reached to a value of 324 HV2, which is comparable with the hardness of quenched and tempered steels.

Mechanical, intergranular corrosion, and wear behavior of aluminum-matrix composite materials reinforced with nickel aluminides

This article presents experimental results of important properties of aluminum-matrix (AA 2014) composite materials reinforced with different intermetallics of the Ni-Al system. For the present study, the intermetallics are prepared either by mechanical alloying (MA) or by gas atomization (GA). The reinforced composite materials were manufactured by mixing the constituents, followed by uniaxial compacting of a preform and subsequent extrusion without canning or degassing. The present study considered the materials in the extruded state and after T6 heat treatment. Assessments were made from the viewpoint of microstructure (by means of optical and scanning electron microscopy (SEM)) and thermal characteristics (by differential scanning calorimetry (DSC)), with special emphasis on studying the reactions that take place between the matrix and the reinforcement and which produce a highly copper-enriched interphase. A study was also made of the effect of this reactivity on the mechanical properties and wear behavior of the composite materials, as well as the intergranular corrosion resistance of the materials in the extruded state.

Fabrication and Mechanical Properties of Aluminum Matrix Composite Materials

Aluminum matrix composite materials containing SiC whisker and Saffil alumina short fiber are fabricated by the direct squeeze infiltration method. Optimum processing conditions for preforms and squeeze casting are suggested. For minimum damage of the reinforcements, the relatively low pressure of 25 MPa is applied.