晶粒大小对AZ31镁合金绝热剪切敏感性的影响

为了研究晶粒尺寸对镁合金绝热剪切敏感性的影响,采用等通道转角挤压(ECAP)技术对AZ31镁合金进行了不同程度的晶粒细化并采用分离式Hopkinson压杆对细化后的AZ31镁合金试样进行了动态剪切试验.采用光学显微镜、扫描电子显微镜、透射电子显微镜和维氏硬度计,分别对冲击压缩后的AZ31镁合金试样进行了组织观察和硬度测试.结果表明,晶粒越小,AZ31镁合金的绝热剪切敏感性越弱.在对绝热剪切带及其周围组织进行维氏硬度测量时发现,剪切带内细小晶粒区的硬度明显高于其周围组织的硬度.

Effect of grain size on adiabatic shear sensitivity of AZ31 magnesium alloy

In order to study the effect of grain size on the adiabatic shear sensitivity of AZ31 magnesium alloy, the grains of AZ31 magnesium alloy were refined with the equal channel angular pressing （ECAP） technology, and the dynamic shear experiments for the cap shaped samples of refined AZ31 magnesium alloy were carried out with the split Hopkinson pressure bar （SHPB）. In addition, the microstructure observation and hardness test for the AZ31 magnesium alloy samples subjected to the impact compression were performed with the optical microscope （OM）, scanning electron microscope （SEM）, transmission electron microscope （TEM） and Vickers hardness tester, respectively. The results show that the smaller the grain size is, the weaker the adiabatic shear sensitivity of AZ31 magnesium alloy is. The hardness test for the shear band and its surrounding microstructures reveals that the hardness of the fine grain zone within the shear band is obviously higher than that of the microstructures around the adiabatic shear band.