Impact of high Al2O3 content on the microstructure, mechanical properties, and wear behavior Al–Cu–Mg/Al2O3 composites prepared by mechanical milling

Metal matrix composites are increasingly being recognized as new wear-resistant materials. The main purpose of this study is to investigate the microstructure, mechanical properties, and wear resistance of Al–Cu–Mg alloy matrix composites reinforced with high contents of Al2O3 particles. Moreover, the effects of 10, 20, and 40 wt% Al2O3 contents on the microstructure, mechanical properties, and dry wear resistance of the Al–Cu–Mg matrix composites are studied. The results show that the θ (CuAl2) phase ratio increases with increasing Al2O3 contents. The hardness values of the samples also increase with increasing Al2O3 contents. The highest tensile and flexural strengths are measured as 284 and 562.9 MPa, respectively, and these values are obtained for the composite material reinforced with 10 wt% Al2O3 particles. The continuous increase in the hardness of the samples with increasing Al2O3 content may cause the lowest volume loss for the 40 wt% Al2O3-reinforced composite. The friction surfaces show that the wear surfaces comprise adhesion, delamination, and smear layers. Overall, compared to the Al2O3-reinforced composite samples, pure Al–Cu–Mg alloy samples show approximately 2 times more mass gain.