Particle Reinforced Aluminium Alloy Composites Research Articles

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

Fabrication of particle-reinforced aluminum alloy composite: role of casting and rolling

ABSTRACT In this study, Al0.5CoCrFeNi high-entropy alloy particles (HEAp) were added to aluminum alloy 2024 to prepare aluminum alloy matrix composites. The composites were prepared via melting, casting, and subsequent rolling (hot rolling, cold rolling, or cryorolling). The results reveal that the adding of HEAp can significantly refine the grains during casting. The cryorolled AA2024 matrix composite with 1 weight percent HEAp content had a tensile strength of 543 MPa and 10% elongation. The Al-Cu crystalline phase of the aluminum matrix composites was more finely dispersed after the addition of an appropriate HEAp content and cryorolling, which led to an increase in both strength and ductility.

Effect of Particle Size on Wear of Particulate Reinforced Aluminum Alloy Composites at Elevated Temperatures

The present paper describes the effect of particle size on operative wear mechanism in particle reinforced aluminum alloy composites at elevated temperatures. Two composites containing zircon sand particles of 20-32 μm and 106-125 μm were fabricated by stir casting process. The dry sliding wear tests of the developed composites were performed at low and high loads with variation in temperatures from 50 to 300 °C. The transition in wear mode from mild-to-severe was observed with variation in temperature and load. The wear at 200 °C presented entirely different wear behavior from the one at 250 °C. The wear rate of fine size reinforced composite at 200 °C at higher load was substantially lower than that of coarse size reinforced composite. Examination of wear tracks and debris revealed that delamination occurs after run in wear mode followed by formation of smaller size wear debris, transfer of materials from the counter surfaces and mixing of these materials on the contact surfaces. The volume loss was observed to increase with increase in load and temperature. Composite containing bigger size particles exhibit higher loss under similar conditions.

Abrasive wear behaviour of B4C particle reinforced Al2024 MMCs

In this study, the effects of volume fraction and particle size of boron carbide on the abrasive wear properties of B4C particle reinforced aluminium alloy composites have been studied. For this purpose, a block-on-disc abrasion test apparatus was utilized where the samples slid against the abrasive suspension mixture at room conditions. The volume loss, specific wear rate and roughness of the samples have been evaluated. The effects of sliding time, particle content and particle size of B4C particles on the abrasive wear properties of the composites have been investigated. The dominant wear mechanisms were identified using scanning electron microscopy. The results showed that the specific wear rate of composites decreased with increasing particle volume fraction. Furthermore, the specific wear rate decreased with increasing the size of particle for the composites containing the same amount of B4C. Hence, it is deduced that aluminium alloy composites reinforced with larger B4C particles are more effective against the abrasive suspension mixture than those reinforced with smaller B4C particles.

Microstructure and abrasive wear behaviour of B4C particle reinforced 2014 Al matrix composites

In this study, the microstructure and abrasive wear properties of varying volume fraction of particles up to 12% B4C particle reinforced 2014 aluminium alloy metal matrix composites produced by stircasting method was investigated. The density, porosity and hardness of composites were also examined. Wear behaviour of B4C particle reinforced aluminium alloy composites was investigated by a block-on-disc abrasion test apparatus where the samples slid against the abrasive suspension mixture (contained 10 vol.% SiC particles and 90 vol.% oil) at room conditions. Wear tests performed under 92 N against the abrasive suspension mixture with a novel three body abrasive. For wear behaviour, the volume loss and specific rate of the samples have been measured and the effects of sliding time and the content of B4C particles on the abrasive wear properties of the composites have been evaluated. The dominant wear mechanisms were identified using SEM. Microscopic observation of the microstructures revealed that dispersion of B4C particles was generally uniform while increasing volume fraction led to agglomeration of the particles and porosity. The density of the composite decreased with increasing reinforcement volume fraction but the porosity and hardness increased with increasing particle content. Moreover, the specific wear rate of composite decreased with increasing particle volume fraction. The wear resistance of the composite was found to be considerably higher than that of the matrix alloy and increased with increasing particle content.

Computational investigation of testing parameter effects on abrasive wear behaviour of AL2O3 particle-reinforced MMCS using statistical analysis

The wear rate model of 7.3 vol.% Al2O3 particle-reinforced aluminium alloy composites with 16 and 66 µm particle sizes fabricated by molten metal mixing method was developed in terms of applied load, particle size of reinforcement, abrasive grain size and sliding distance based on the Taguchi method. The two-body abrasive wear behaviour of the specimens was investigated using a pin-on-disc abrasion test apparatus where the sample slid against different SiC abrasives under the loads of 2 and 5 N at the room conditions. The orthogonal array, signal-to-noise ratio and analysis of variance were employed to find out the optimal testing parameters. The test results showed that particle size of reinforcement was found to be the most effective factor among the other control parameters on abrasive wear, followed by abrasive grain size. Moreover, the optimal combination of the testing parameters was determined and predicted. The predicted wear rate results were compared with experimental results and found to be quite reliable.

Pre-treatment process of B4C particles to improve incorporation into molten AA2014 alloy

The properties of particle-reinforced aluminum alloy composites depend on the microstructure and evolved uniformity distribution of particles in the matrix, wettability of particles by the melt and chemical reactions between particles and matrix. The wettability of B4C particles by the molten aluminum alloys is generally poor below 1100 °C making their incorporation difficult. In this study, in order to improve incorporation of the B4C particles by AA2014 alloy melt a novel pre-treatment process was presented and B4C-2014 Al composites containing B4C particles up to 12 vol.% were manufactured by using stir casting. SEM observations have shown that uniformity distribution of B4C in the matrix was satisfactory and there was no reaction at the particle-matrix interface due to low processing temperature. However clustering of B4C particles was observed in relatively high particle-containing composites, which is commonly associated with the casting route.

Effect of microstructure on Young’s modulus of extruded Al–SiC composites studied by resonant ultrasound spectroscopy

In this work, an attempt was made to correlate the Young’s modulus of SiC particle reinforced aluminum alloy composites, measured by resonant ultrasound method, to reinforcement spatial distribution. Composites were fabricated by extrusion of billets that were previously formed using cold pressing blend of matrix alloy powders and ceramic particles. It has been shown that more aggregated microstructures were generated with an increase in ceramic volume fraction (to 20%) and the matrix alloy powder mean particle size from 40 to 180 μm as well as with a decrease in the reinforcement particle size (3–14 μm). At the same time, ultrasonic wave velocity as well as Young’s modulus diminish with a decrease in SiC content and its particle size, and with increase in matrix alloy particle size. The analysis showed that it could be partly attributed to the higher amount of residual porosity in agglomerated structures. An addition decrease of elastic characteristics was attributed to the increasing influence of mechanically imperfect contacts that formed between ceramic particles in the more aggregated microstructures.

Evaluation of material properties of SiC particle reinforced aluminum alloy composite using neutron and X-ray diffraction

The phase stresses under loading in a monolithic aluminum alloy and an aluminum alloy reinforced with silicon carbide particles were measured by the neutron diffraction method. Under uniaxial loading, the longitudinal and transverse strains in each constituent phase were measured. The diffraction elastic constants for each diffraction plane were investigated as a function of the diffraction intensity by TOF. Single peak analysis was carried out for each diffraction profile. The measured results were compared with the theoretical micromechanical models such as the self-consistent and Mori–Tanaka method using the Eshelby theory (MTE). The accuracy of the elastic constant strongly depends on the diffraction intensity. In order to confirm the rule of mixture, the phase stress was measured by the X-ray method. The macrostress calculated by the rule of mixture agreed very well with the applied stress. Finally, fatigue damage was evaluated by the neutron method. The change of the full width at half maximum in the aluminum phase during fatigue is small. On the other hand, the value in the SiC phase increased steeply just before fracture.

Influence of microstructure and experimental parameters on the erosion–corrosion behavior of Al alloy composites

The influence of material related parameters such as alloy composition and reinforcement volume fraction and the experimental parameters such as the slurry concentration and rotational speed on the erosion–corrosion behavior of SiC particle reinforced aluminum alloy composites in saline, acidic and basic environments is studied. It is observed that 2014–SiC composite exhibited better wear resistance than LM13–SiC composite in acidic and NaCl media. Further both the composites exhibited better wear resistance than their matrix alloys in these environments irrespective of the sand content in the slurry and the rotational speed. The wear rates increased with increasing sand content in both the media. Al/Si/precipitate interfaces were found to be the preferential sites for corrosive attack in both the alloys and composites. In basic media the trend was reversed with both the composites exhibiting lower wear resistance than their matrix alloys. Further 2014–SiC composite exhibited lower wear resistance than LM13–SiC composite in basic media.

Analyses of metallurgical behavior of Al–SiCp composites after ballistic impacts

The dynamic failure of SiC particle reinforced aluminum alloy composite; AA5083 is studied under ballistic impact loading. Tests were done with two different projectile types, AP (Army Piercing) 7.62 and 9 mm, and the hole surfaces created by the projectiles were investigated using both optical and scanning electron microscopy. Examination of the hole surface of the composite after dynamic failure showed microscopically ductile failure in the matrix following brittle cracking of the particles. The dynamic failure process involved both matrix and particle cracking. The high velocity of the projectile led to the melting of some surface layers because of the excess heat resulting from high velocity friction. Because of high friction, some melted regions had a porous structure due to shrinkage during rapid solidification caused by the high-speed projectile at the hole surface. The type of projectile strongly influenced the damage formation and the deformation type was also affected by the backing condition.

Preparation and some properties of SiC particle reinforced aluminium alloy composites

Abstract Aluminium alloy composites containing various particle sizes of 10 and 20 wt.% SiC particles were prepared by molten metal mixing and squeeze casting method under argon gas. The stirring was carried out with graphite impeller during addition of particle. The molten mixture was poured into a die when the stirring was completed and metal matrix composites were produced by applying the pressure. Optical microscopic examination, hardness, density and porosity measurement were carried out. Moreover, metal matrix composites were machined at various cutting speeds under a fixed depth of cut and feed rate using different cutting tools. It is observed that there was a reasonably uniform dispersion of particles in the matrix alloy. The density decreased with decreasing particle sizes, but porosity decreased considerably with increasing particle size. In addition, the tool life decreased considerably with increasing cutting speeds for all tests. Among cutting tools, the wear resistance of Al2O3 coated tools showed better performance than those of the other tools without chip breaker geometries in the machining of SiCp-reinforced composites.

Tool wear and surface roughness of Al 2O 3 particle-reinforced aluminium alloy composites

The machinability of 2024 aluminium alloy reinforced with Al 2O 3 particles using varying size and weight fraction of particles up to 30 wt.% by a vortex method was carried out at different cutting conditions. Experiments were carried out with TiN (K10) coated carbide tools and TP30 coated carbide tools at various cutting speeds. Tool wear and surface roughness in the turning of Al 2O 3 particle-reinforced aluminium alloy composite was investigated with special attention paid to the effects of material structures. The experimental results showed that tool life increased with increasing the cutting speed for both cutting tools and the tool life of TiN (K10) tool was significantly longer than that of TP30 tool. It is observed that the major wear form of the tools are the combination of rounding of nose and flank wear in addition to removal of coated layer from the substrate for the TiN (K10) tool but edge chipping and rounding of nose was evident for the TP30 tool. Moreover, the optimum surface roughness was obtained at a speed of 160 m min −1 while the maximum surface roughness value was found in the machining of the 10% Al 2O 3 composites with particle size of 16 μm. The surface roughness also increased with the increasing weight percentage of the particles. Furthermore, physical appearance of chips produced by TiN (K10) cutting tools were discontinuous and smaller sizes while the appearance of chips produced by TP30 cutting tools were continuous type and larger size.

Detection of particle damage event by acoustic emission during tensile straining of SiC particle reinforced aluminium alloy composites

The fracture mechanisms of composites which contain coarse second phase (30 µmSiC) have been studied by acoustic emissions measurement. The fracture mechanism for these composites is different from that for composites containing small particles. In the latter case, it is well known that the void nucleation during fracture occurs at interface between matrix and reinforcement. The experimental data and the current model for fracture were compared, and fracture strain has been estimated using a modified particle fracture model based on the Evensen void growth model. Acoustic emissions were detected from fractured particle, although there are some differences in AE responses caused by difference in heat treatment. Void nucleation occurs by particle fracture in all of the materials. A modified equation for the fracture strain has been proposed and this equation provides a good quantitative agreement with experimental data.

Dry sliding wear of TiB2 particle reinforced aluminium alloy composites

Al–4 wt-%Cu alloy and composites reinforced with 10 and 20 vol.-% of TiB2 particles were prepared by powder metallurgy followed by hot isostatic pressing. The dry sliding wear behaviour of specimens of these materials was investigated. Pin-on-disc measurements showed that the wear resistance of Al–4Cu alloy can be improved dramatically by the addition of 20 vol.-%TiB2 particles. This was due to the high hardness of the TiB2 particles, and to strong particle–matrix bonding. The wear data were found to correlate with SEM observations.

Fabrication of nanocrystalline ZrO 2 particle reinforced aluminum alloy composite by squeeze casting route

L. Genlgl*, S. 0chiai2, H.X. Peng3, Lian Gao4, Jing Sun4 and Z.Q. Sun3 ’ School of Materials Science and Engineering, Harbin Institute of Technology, Harbin, P.R. China 2 Mesoscopic Materials Research Center, Faculty of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-01, Japan 3 School of Materials Science and Engineering, Beijing University of Science and Technology, Beijing 100083, P.R. China 4 Shanghai Institute of Ceramics, Chinese Academy of Science, 1295 Ding Xi Road, Shanghai 200050, P.R. China

Coating of SiC with ti by chemical vapour deposition

Silicon carbide particle reinforced aluminium alloy composites have been studied. One of the most important problems with metal matrix composites is low interfacial bonding strength between reinforcement and matrix, which results in poor mechanical properties. This work studied the coating method with the aim of improving interfacial bonding between SiC particles and Al alloy. Titanium coated SiC plates and particles were prepared by plasma enhanced chemical vapour deposition (PECVD) using the reactant system TiCl4–H2. Continuous and adherent films on the SiC plates and particles were obtained by PEC VD treatment for 2 min. Treatment by PECVD for periods greater than 2 min resulted in crack formation and agglomeration of particles. Chlorine content in the films was reduced by using laser CVD as compared with PECVD.

A model for the abrasive wear resistance of multiphase materials

A theoretical model for estimating the abrasive wear resistance of multiphase materials and composites from the wear resistance of the constituents is proposed. Starting from Archard's equation, two rules for the dependence of the amount of reinforcing phase, corresponding to two wear modes, have been derived. These rules of mixture, constitute estimations of the upper and lower limits for the wear resistance of a composite. The theory also results in two corresponding formulations of the wear equation generalised to multiphase materials. The applicability and limitations of the theory are discussed. The validity of the theory is supported by results from two test series. Three-body abrasive tests with silicon carbide abrasives were performed on simple specially fabricated model composites and silicon carbide particle-reinforced aluminium alloy composites were tested in two-body abrasion against silicon carbide and flint abrasives. The model serves to clarify the roles of the matrix and the reinforcing phase of a composite in resisting wear. The model can be instrumental in estimating upper and lower limits of wear and in indicating how to redesign a composite or modify a tribosystem (changing load, filtering abrasive particles, etc.) to transform the wear of a multiphase material towards the least severe mode.