Microstructure, Mechanical Properties and Wear Resistance of As-Cast Mg-3Al-1Ca-0.4Mn/Tip Magnesium Matrix Composites

In this paper, microstructure, mechanical properties and wear resistance of as-cast Mg-3Al-1Ca-0.4Mn/Tip magnesium matrix composites were investigated. As-cast Mg-3Al-1Ca-0.4Mn/xTip (x = 0, 1, 2, and, 3wt%) composites were prepared using a combination of mechanical stirring and permanent mold casting. The results showed that nanoscale interfacial products (Al₂Ti phases) were precipitated at Ti/Mg interfaces, which contributed to the formation of strong interfacial bonding. Compared with matrix alloys, Mg-3Al-1Ca-0.4Mn/2Tip composites had better mechanical properties and wear resistance with ultimate tensile strength, yield strength, elongation, hardness and wear rate of 149 MPa, 86 MPa, 8.6%, 46 HBW and 8.4×10^-3 mm³/(N m), which indicated significant improvements of 26%, 38%, 36%, 10% and 59% over the Mg-3Al-1Ca-0.4Mn alloys, respectively. Grain refinement, load transfer and strong interfacial bonding all had important effects on improving mechanical properties of composites. The increased wear resistance of composites was mainly attributed to the incorporation of high hardness phases and the formation of protective oxide films.