(1. 安阳工学院 机械工程学院，安阳 455000；
2. 河南理工大学 材料科学与工程学院，焦作 454000；
3. 安阳工学院 安阳市先进航空材料与加工技术重点实验室，安阳 455000)
摘 要: 采用电子背散射衍射(EBSD)研究了1060铝/AZ31B镁异种金属搅拌摩擦焊(FSW)接头的晶粒组织、织构演化和力学性能。结果表明：接头组织中从热影响区(HAZ)至焊核区(NZ)，低角度晶界(LAGBs)百分比和平均晶粒粒径均逐渐减少。在HAZ，晶粒组织与母材相似，热机械影响区(TMAZ)则发生了动态再结晶，形成了粗晶粒和细小等轴晶粒共存的显微组织，而NZ由均匀细小的等轴晶组成。HAZ织构与母材相似，铝侧NZ形成了{001}〈100〉再结晶立方织构，在NZ中心，镁晶粒取向从〈0001〉||ND向〈0001〉||WD偏转，而在镁侧NZ，晶粒的取向为〈0001〉||TD。接头的抗拉强度为96.1 MPa，伸长率为13.2%，分别达到1060铝合金母材抗拉强度的95%和伸长率的65%。铝侧HAZ位错密度减小导致的材料软化以及铝侧HAZ与TMAZ之间晶粒粒径的差异促使接头从铝侧HAZ/TMAZ界面附近断裂。
关键字: 铝/镁异种金属搅拌摩擦焊；晶粒组织；织构演化；力学性能；断裂机理
（1. School of Mechanical Engineering, Anyang Institute of Technology, Anyang 455000, China;
2. School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China;
3. Anyang Key Laboratory of Advanced Aeronautical Materials and Processing Technology, Anyang Institute of Technology, Anyang 455000, China）
Abstract:The grain structure, texture evolution and mechanical properties of friction stir welded dissimilar metal joints of 1060 aluminum and AZ31B magnesium alloys were studied by electron backscatter diffraction (EBSD). The results show that the proportion of low angle grain boundaries (LAGBs) and average grain size decrease gradually from heat affected zone (HAZ) to nugget zone (NZ). In HAZ, the grain structure is similar to that of the base metals, while dynamic recrystallization occurs in the thermo-mechanical affected zone (TMAZ), forming a microstructure in which coarse grains and fine equiaxed grains coexist. NZ is composed of uniform and fine equiaxed grains. The texture of HAZ is similar to that of base metals. The {001}〈100〉 recrystallized cubic texture is formed in the Al-side NZ. At the NZ center, the grain orientation of magnesium grains deflects from the 〈0001〉|| normal direction (ND) to 〈0001〉|| welding direction (WD), while at the Mg-side NZ, the orientation of grains is 〈0001〉|| transverse direction (TD). The tensile strength of the joint is 96.1 MPa and the elongation is 13.2%, reaching 95% of the tensile strength and 65% of the elongation of 1060 aluminum alloy base metal respectively. The material softening caused by the decrease of HAZ dislocation density on the aluminum side and the difference of grain size between HAZ and TMAZ on the Al-side jointly promote the fracture of the joint near the Al-side HAZ/TMAZ interface.
Key words: Al/Mg dissimilar metal friction stir welding; grain structure; texture evolution; mechanical property; fracture mechanism
