Microstructure and tensile properties of rapid-cooling friction-stir-welded AZ31B Mg alloy along thickness direction  

AZ31B镁合金快速冷却搅拌摩擦焊缝厚度方向的显微组织和力学性能

作　　者：Nan XU Wei-da ZHANG Si-qi CAI Yue ZHUO Qi-ning SONG Ye-feng BAO 许楠;张伟达;蔡思奇;卓越;宋亓宁;包晔峰(河海大学机电工程学院,常州213022)

机构地区：[1]College of Mechanical and Electrical Engineering,Hohai University,Changzhou 213022,China

出　　处：《Transactions of Nonferrous Metals Society of China》2020年第12期3254-3262,共9页中国有色金属学报（英文版）

基　　金：Project(51805145)supported by the National Natural Science Foundation of China;Project(CJ20200076)supported by the Changzhou Science and Technology Program,China;Project(B200202229)supported by the Fundamental Research Funds for the Central Universities of China;Project(2020102941517)supported by Hohai University Undergraduate Innovation and Entrepreneurship Training Program,China。

摘　　要：Rapid-cooling friction-stir-welding(FSW)was used to join AZ31B magnesium alloy plates of 6 mm in thickness.The microstructure and mechanical properties in thickness direction were carefully investigated with electron backscattered diffractometer,and transmission electron microscope.The obtained results showed that ultrafine grains with high dislocation density were obtained in the top region of the weld due to liquid CO2 cooling.A large number of{1012}twins and second-phase particles were also induced in these refined grains.The basal texture intensity was significantly reduced due to the appearance of{1012}twins.The top region showed the higher strength and elongation compared with the bottom region,and the welding efficiency reached 93%.This work provided a simple and efficient strategy for manufacturing a gradient structure in the FSW Mg alloy joint.采用电子背散射衍射仪和透射电子显微镜研究快速冷却对6 mm厚AZ31B镁合金搅拌摩擦焊缝厚度方向的显微组织和力学性能的影响。结果表明,液态二氧化碳冷却可促进焊缝顶部形成具有高位错密度、大量{1012}孪晶和第二相颗粒的细晶结构。{1012}孪晶使焊缝顶部区域的基面织构显著降低。接头顶部区域的强度和断后伸长率较底部区域均明显提高,焊接效率可达93%。这为在镁合金搅拌摩擦焊接头中制备梯度结构提供一种简单有效的方法。

关 键 词：friction stir welding magnesium alloy RECRYSTALLIZATION texture MICROSTRUCTURE mechanical properties 

分 类 号：TG453.9[金属学及工艺—焊接]