Hot deformation and wear resistance of P/M aluminium metal matrix composites

Hot compression and wear resistance as well as hardness of powder metallurgy (P/M) aluminium metal matrix composites (MMC) were investigated. Metal matrix composites were manufactured using powder metallurgy technique of ball milled mixing in a high energy attritor and cold compaction followed by hot extrusion at 500 °C. Matrix of pure aluminium was used to which different weight fractions of Al2O3 and Al4C3 particles were added as follows: Al + 1.5% Al2O3, Al + 1.5% Al2O3 + 4.0% Al4C3 and Al + 1.5% Al2O3 + 12.0% Al4C3. Compression tests were performed at different temperatures ranging between room temperature and 300 °C. While, wear tests were carried out using a pin-on-disk testing machine with a gray cast iron automotive rotor drum as a counter face under different normal loads (5–20 N) and different sliding velocities of 1.09, 1.64, 2.18 and 3.27 m/s at an abraded distance of 200 m. Generally, both hardness and compressive strength were enhanced by the addition of Al2O3 and Al4C3 and their magnitudes continued to improve up to deformation temperature of 150 °C. The ductile–brittle transition phenomenon was obtained at an addition of Al4C3. Also, the addition of 4% Al4C3 improved the wear resistance of composites, while its existence decreased the braking percent.