Effect of Different Mg2Si Concentrations on the Wear Properties and Microstructure of Mg2Si/Al-5 wt.% Cu Composites

In this paper, x wt.% Mg2Si/Al-5 wt.% Cu (x = 5, 10, 15, 20, and 25) composites were prepared by an in situ process. The effect of phase content of Mg2Si on their microstructures and performances was investigated; the dry sliding wear behavior under room temperature was examined. The results show that with the increase in Mg2Si (Mg and Si) concentration, the microstructure of the Al-Mg2Si composite changes significantly. The eutectic microstructure changes from lamellar labyrinth to long rod, along with the long-range order Al2Cu phase to island and plate-like morphology, and the primary Mg2Si phase becomes more compact. The hardness increases from 117 HV to 163 HV. The friction coefficient, wear rate, wear width, and wear depth decrease from 0.368 +/- 0.048, 2.7 x 10(-5) mm(3)/m, 1.93 mm, and 133.3 mu m to 0.315 +/- 0.016, 1 x 10(-5) mm(3)/m, 0.94 mm, and 70.2 mu m, respectively. The tested composites worn surfaces exhibit adhesion, peeling, microcutting wear, abrasive, and oxidation.