温度和加载方向对挤压态AZ31镁合金动态压缩行为及显微组织的影响  

Effects of Temperature and Loading Direction on Dynamic Compression Behavior and Microstructure of Extruded AZ31 Magnesium Alloy

作　　者：卢立伟[1] 赵俊[1] 刘龙飞[1] 王亚平[1] 陈志钢[1] 

机构地区：[1]湖南科技大学机电工程学院,湘潭411201

出　　处：《机械工程材料》2014年第11期35-39,65,共6页Materials For Mechanical Engineering

基　　金：湖南省自然科学基金资助项目(14JJ3111);校博士科研启动基金资助项目(E51353);湖南省自然科学湘潭联合基金资助项目(12JJ9011)

摘　　要：利用分离式Hopkinson压杆系统对具有混晶组织的挤压态AZ31镁合金在高温下的动态压缩行为进行了研究,分析了显微组织在动态压缩前后的演变,讨论了试验温度和加载方向对动态压缩行为和组织的影响。结果表明:加载方向与挤压方向平行时,其真应力-应变曲线随温度升高呈下降的趋势;加载方向垂直于挤压方向在200℃以上压缩时,温度对真应力-应变曲线的影响不明显;在压缩变形过程中,动态再结晶伴有孪晶形核和位错形核机制;随温度的升高,变形机制由孪生逐渐转变为滑移,加载方向垂直于挤压方向的试样转变得更为明显;在300℃压缩变形时,原始的混晶组织得到显著细化。Dynamic compression behavior of extruded AZ31 magnesium alloy at high temperature were studied using the system of separated hopkinson pressure bar,and the microstructure evolution before and after dynamic compression was analyzed and the effects of temperature and loading direction on dynamic compression behavior and microstructure were discussed.The results show that,for loading direction parallel to extrusion direction specimens,true stress-true strain curve presented descend trends with the increase of temperature;however,as for loading direction perpendicular to extrusion direction samples above 200 ℃,temperature had no significant influence on true stress-true strain curve.Besides,the mechanism of dynamic recrystalization during the dynamic compression process could be attributed to twin nucleation and dislocation nucleation.Deformation mechanism gradually transferred from twinning to slip with the increase of temperature,and this phenomenon was more obvious for loading direction perpendicular to extrusion direction samples.Primitive mischcrystal structure could be refined remarkably by compression deformation at temperature of 300 ℃.

关 键 词：AZ31镁合金 加载方向 动态压缩行为 孪生 动态再结晶 

分 类 号：TG146.2[一般工业技术—材料科学与工程]