采用常规热挤压方法制备Mg?1Mn?0.5Al?0.5Ca?0.5Zn合金,挤压温度为673 K,挤压比为25:1,并进行473 K时效处理.采用扫描电镜、电子背散射衍射和透射电镜表征合金的显微组织,测试试样的温室拉伸性能.结果表明,经473 K、1 h峰值时效后,试样出现细小等轴晶,平均晶粒尺寸为1.7μm,Al?Ca颗粒面积分数明显增多.热挤压后仍能观察到位错和位错.峰值时效态样品表现出高强度和良好塑性,其抗拉强度为320 MPa,屈服强度为314 MPa,伸长率为19％.“,”Mg?1Mn?0.5Al?0.5Ca?0.5Zn (wt.％) alloy was fabricated by conventional extrusion at 673 K with an extrusion ratio of 25:1, followed by aging at 473 K. The microstructure was characterized by scanning electron microscopy, electron back-scattered diffraction, and transmission electron microscopy. The mechanical properties were determined by the tensile test. The peak-aged sample shows fine recrystallized grains with an average grain size of 1.7 μm. Area fraction of Al?Ca particles in the alloy increases significantly after peak aging. Meanwhile, both and dislocations were observed to remain in the alloy after hot extrusion. Thus, the peak-aged sample exhibits simultaneously high strength and good ductility with the ultimate tensile stress, tensile yield stress, and tension fracture elongation of 320 MPa, 314 MPa, and 19.0％, respectively.