Synthesis of Microstructure and Tribological Properties of AMMCs Fabricated by Two Different Powder Metallurgy Routes

Abstract

In this investigation tribological properties of Aluminium-Alumina metal matrix composites (AMMCs) are developed through developing microstructure and improving physical properties by controlling process parameters of two different powder metallurgy routes. In one route; 5, 10 and 15 weight percent Alumina (Al2O3) powder was manually blended with pure Aluminium (Al) and compacted at 10 ton/inch2 uniform pressure followed by sintering at 400°C, 500°C and 600°C for 30 minutes. Alternately, commercially pure Al powder was oxidized at 500°C, 600°C, 700°C and 800°C for 15, 30 and 45 minutes individually followed by same powder metallurgy process as applied in the first route of AMMCs fabrication like blending, compacting and sintering. Optical micrographs of fabricated AMMCs were taken and corelated with the apparent porosity of fabricated AMMCs as well as with different process parameters and variables like sintering and oxidation temperatures, oxidation duration, and wt. % of Alumina. Tribological properties of all AMMCs were also measured and corelated with the process parameters and variables as well as with the observed microstructure and measured apparent porosity. It is observed that finer grain structures are developed by increasing sintering and oxidation temperatures, and oxidation duration. It is also observed that wear resistance of AMMCs is enhanced by increasing sintering and oxidation temperatures, oxidation duration, and wt. % of Alumina individually; whereas, more enhancement is observed in case of second route of AMMCs fabrication. Therefore, the uniqueness of this investigation is to improve the wear resistance of pure Aluminium by fabricating AMMCs through simply heating pure Al powder at different temperatures followed by powder metallurgy process instead of adding reinforcement material (Alumina powder).