铸态Mg-5Sn-(0～2)Cu合金的显微组织,力学性能和蠕变性能（英文）

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

利用XRD，SEM手段研究了铸态Mg-5Sn-（0～2．0）Cu合金的显微结构。结果表明Mg-5Sn合金由枝晶状的α—Mg和Mg2Sn相组成，Cu的加入使合金出现Mg2Cu相。随着Cu含量的增加，晶粒逐渐细化，Mg2Sn相和Mg2Cu相的量也逐渐增加，但是这两种相的尺寸亦随之增加。室温拉伸结果表明，Cu质量分数在0．5％-1．0％时对合金起促进作用，然而，过多的Cu会弱化合金的拉伸性能。Mg-5Sn-1．0Cu合金具有最优的力学性能，抗拉强度达到180MPa，延伸率达到12％。合金在温度为175℃，载荷为35～75MPa的压蠕变性能表明，Cu可以提高Mg-Sn合金的抗蠕变性能。

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 a-Mg and Mg2Sn phase, Mg2Cu appears in the Cu containing alloys. The addition of Cu results in obvious grain refinement. With Cu content increasing, the amounts of Mg2Sn and Mg2Cu 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 ℃ 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.