The microstmcture evolution of ZK60 alloy during ECAP process was investigated by optical microscopy, electron backscattered diffractometry (EBSD) and transmission electron microscopy (TEM). The results show that, after one pass of equal channel angular pressing (ECAP) process at 240 °C, the grain size of ZK.60 alloy is significantly refined. However, the grain size distribution is not homogeneous. The microstructure prior to shear deformation is consisted of coarse grains and twins. The microstructure in the shear zone is mainly shear bands and dynamic recrystallized grains. After shear deformation, the grain structure is mainly dynamic recrystallized grains. The grain refinement mechanism for ECAP of ZK60 alloy is comprehensive effect of shear deformation and dynamic recrystallization.%采用金相显微镜、背散射电子衍射(EBSD)和透射电子显微镜(TEM)分析ZK60镁合金在等通道转角挤压(ECAP)过程中不同部位的显微组织特征.结果表明:ZK60镁合金经240℃ECAP变形1道次后,合金的晶粒得到明显细化,但组织仍不均匀.剪切变形前,合金组织主要为粗大晶粒并伴有大量孪晶,剪切区的组织主要为剪切变形带和少量再结晶组织；剪切变形后,合金的晶粒组织主要为再结晶组织；合金ECAP过程的晶粒细化主要为机械剪切和动态再结晶的综合作用.
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