Microstructure, Mechanical Properties and Compressive Creep Behavior of as-Cast Mg-5Sn-(0∼2)Cu Alloys

Abstract The microstructures of the as-cast Mg-5Sn alloys with 0.5wt%, 1wt%, and 2wt% Cu addition were characterized by XRD and SEM. The results show that besides α-Mg and Mg 2 Sn phase, Mg 2 Cu appears in the Cu containing alloys. The addition of Cu results in obvious grain refinement. With Cu content increasing, the amounts of Mg 2 Sn and Mg 2 Cu increase, but the sizes of these two intermetallics coarsen. The tensile test at the ambient temperature shows that when Cu content is in the range of 0.5wt%∼1.0wt%, the Cu addition helps to improve the strength of the alloys; however, excessive Cu addition leads to the deterioration of the ultimate strength. The optimum mechanical property is attained at Mg-5Sn-1.0Cu alloy, where the UTS and the elongation reach 180 MPa and 12%, respectively. The behavior of the Mg-Sn-Cu alloy in the compressive creep at 175 °C at applied load of 35∼75 MPa was also investigated, which shows that the Cu addition helps to improve the compressive creep resistance of Mg-Sn alloy.