低速热变形对挤压态Mg-Zn-Mn合金组织及力学性能的影响  

Effects of low-speed hot deformation on microstructure and mechanical properties of as-extruded Mg-Zn-Mn alloy

作　　者：康宏辉 张至柔[1] 张宇修 长海博文 杨续跃[1] KANG Hong-hui;ZHANG Zhi-rou;ZHANG Yu-xiu;NAGAUMI Hiromi;YANG Xu-yue(School of Materials Science and Engineering,Central South University,Changsha 410083,China;School of Iron and Steel,Soochow University,Suzhou 215100,China)

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]苏州大学沙钢钢铁学院,苏州215006

出　　处：《中国有色金属学报》2023年第5期1434-1446,共13页The Chinese Journal of Nonferrous Metals

基　　金：国家重点研发计划资助项目(2021YFB3701100);国家自然科学基金资助项目(52071344,U1864209)。

摘　　要：结合光学显微镜(OM)、电子背散射衍射技术(EBSD)、透射电子显微镜(TEM)等,分析了低速热变形对挤压态Mg-Zn-Mn合金显微组织及室温压缩性能的影响。结果表明:Mg-Zn-Mn合金在200~300℃的低速热压缩过程中存在明显的动态再结晶和动态析出,热压后样品组织明显细化且基面织构减弱。对于热压后样品,其抗压强度和断裂应变随变形温度的升高先增大后减小。对于250℃下热压缩的样品,其抗压强度和断裂应变随热压变形量的增大先减小后增大。其中,在250℃下热压缩且变形量为70%时,合金的性能提升最为显著,在不损害塑性的情况下,其屈服强度(σ0.2)和抗压强度分别达到247 MPa和504 MPa,比挤压态时分别提升了63%和19%。Effects of low-speed hot deformation on microstructural evolution of an as-extruded Mg-Zn-Mn alloy was investigated by optical microscopy(OM),electron back-scattering diffraction(EBSD) and transmission electron microscopy(TEM).The results show that the dynamic recrystallization and dynamic precipitation happen during low-speed hot compression at temperature ranging from 200-300 ℃.Accordingly,the obvious grain refinement and basal texture weakening are observed after compression,resulting in an improvement of mechanical properties.For compressed samples,the compressive strength and fracture strain of the alloy increase firstly and then decrease with the increase of temperature.For the sample compressed at 250 ℃,the compressive strength and fracture strain of the alloy decrease firstly and then increase with the increasing of hot compression strain.Among them,the alloy exhibits the best compressive properties when it is hot compressed at 250 ℃ with strain of 70%.Its yield strength and ultimate compressive strength reach 247 MPa and 504 MPa,respectively,which are increased by 63% and 19%,respectively,comparing to the as-extruded sample,without any drop in plasticity.

关 键 词：镁合金 热压缩 微观组织 动态再结晶 压缩性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]