Effect of Al2O3 amount on microstructure and wear properties of Al–Al2O3 metal matrix composites prepared using mechanical alloying method

This paper reports the outcome of an investigation into the effect of Al2O3 content on the microstructure and wear properties of Al–Al2O3 metal matrix composites. The Al–Al2O3 composites are prepared by a mechanical alloying method using Al2O3 powders up to 20 vol.% as reinforcement. Alloying is performed in a vibration mill using a ball-to-powder ratio 10:1 and a milling time varying from 30 to 100 min at a rate of 710 Hz. The prepared compositions are cold pressed at 630 MPa with a single action and sintered at 560°C for 30 min under Ar gas atmosphere. The experimental results show that the reinforcing phase Al2O3 is homogeneously dispersed in the Al matrix and the interface between Al matrix and Al2O3 is well formed. Wear tests are carried out under dry sliding conditions using a pin-on-disk testing machine at three different loads of 10, 25, and 50 N and at a sliding speed of 2.08 m/sec. Total sliding distances are selected as 400, 800, 1200, and 1600 m. It is seen that the wear rate decreases with increasing Al2O3 content and sliding distance at a sliding speed of 2.08 m/sec.