中文摘要：

通过OM、XRD、TEM、SEM和蠕变试验,研究了时效态Mg-7Gd-2.5Nd-0.8Sb-0.5Zr（质量分数,%）合金的显微组织和高温蠕变行为。结果表明,时效态合金由α-Mg基体和方块相组成。方块相主要分布在晶界处,为富Gd化合物。在300℃、70 MPa条件下合金具有良好的蠕变性能,组织上没有网状析出相,滑移线较多,存在孪晶,有较高的位错密度,此时网状析出相已完全转变为颗粒相。

英文摘要：

The microstructure and high temperature creep behavior of aged Mg-7Gd-2.5Nd-0.8Sb-0.5Zr（mass fraction,%）alloy were investigated by OM, XRD, TEM, SEM and creep experiment. The results show that the aged alloy is composed ofα-Mg matrix and cuboid-shaped phase. Cuboid-shaped phase mainly distributes in the grain boundaries, which is high Gd compounds. The alloy exhibits excellent creep property under the temperature of 300 ℃ and the stress of 70 MPa. The microstructure has no mesh precipitated phase and has more slip line, twin crystals and high dislocation density, and, then the mesh precipitated phase completely transforms into granular phase.