论文部分内容阅读
采用挤压-剪切法(ES)在不同剪切角(150°、135°和120°)下制备了AZ31棒材.采用ES工艺制备的棒材,包括直接挤压和后续剪切两部分.随后采用光学显微镜、扫描电镜和电子背散射衍射(EBSD)等方法研究了具有双峰晶粒结构的AZ31镁合金的显微组织演变,从取向分布图中可清晰的观察到细晶粒包围狭长变形粗晶的混晶结构,且大晶粒区域的占比会随应变的增加而增大.整体来看,因为应变量和动态再结晶分数都会随着剪切角的减小而增加,导致大晶粒的占比增大,而小晶粒尺寸增加.室温压缩实验中,随着剪切角的减小,屈服强度和峰值强度逐渐增大.此外,ES挤压的基面极图也会随着剪切角度的不同发生变化.“,”AZ31 rods were prepared by the extrusion-shear(ES)process with different shearing angles(150°,135° and 120°),including direct extrusion process and subsequent shearing process.Microstructure evolution of AZ31 alloys with bimodal grains was investigated by optical microscopy(OM),scanning electron microscopy and electron back scattered diffraction(EBSD),etc.The results show that proportion of the large grain areas increases with the increase of strain.Bimodal-grained structures are observed by OM,and the narrow coarse grains are surrounded by the fine grains.The pole figures show that the texture changes with different shearing angles of the ES mould.Both the yield strengths and the peak strengths increase with decrease of the shearing angles gradually.As the shearing strain increases,the proportion of large grains increases while the size of small grains increases because both the deformation and the dynamic recrystallization fractions increase with the decrease of shearing angles.