外设凸块法下2A12RFSSW接头微观组织和断裂分析  

Microstructure and Fracture Analysis of 2A12 RFSSW Joint with Outer Convex Block Method

作　　者：贺地求 马力[1,2] 左震 HE Diqiu;MA Li;ZUO Zhen(Light Alloy Research Institute,Central South University,Changsha 410083,China;State Key Laboratory of HighPerformance Complex Manufacturing,Central South University,Changsha 410083,China)

机构地区：[1]中南大学轻合金研究院,湖南长沙410083 [2]中南大学高性能复杂制造国家重点实验室,湖南长沙410083

出　　处：《热加工工艺》2019年第17期15-18,22,共5页Hot Working Technology

基　　金：国家重点基础研究发展计划(973计划)项目(2014CB046605);中南大学研究生科研创新项目(1053320170397)

摘　　要：采用外设6061凸块法对2 mm厚的2A12铝合金板进行回填式搅拌摩擦点焊试验,对点焊接头的宏观形貌、微观组织、硬度分布和断裂行为进行分析。结果表明:接头区大致可分为2A12母材区、热影响区、热机影响区和搅拌区,搅拌区又分为2A12搅拌区和6061搅拌区,2A12搅拌区和6061搅拌区材料发生充分的塑性流动,原子扩散作用较强,形成致密的冶金结合,挤压区底部存在50μm宽的纯铝带。接头断裂模式为剪切-塞型断裂,裂纹沿着挤压区底部纯铝带扩展,剪切载荷均值为9.7 kN。Refill friction stir spot welding (RFSSW) of 2 mm thick 2A12 aluminum alloy plate was carried out by using 6061 outer convex block method.The macroscopic morphology, microstructure, hardness distribution and fracture behavior of spot welded joints were analyzed.The results show that the joint can be divided into 2A12 base material, heat affected zone, thermo-mechanically affected zone and stir zone.The stir zone is divided into 2A12 stir zone and 6061 stir zone.Adequate plastic flow in 6061 stirring zone and 2A12 stirring zone occurs.The atom diffusion is strong, and compact metallurgical bonding forms.There are 50 μm pure aluminum bands at the bottom of the extrusion zone.The fracture mode of the joint is shear plug fracture.The crack propagates along the pure aluminum zone at the bottom of the extrusion zone, and the average shear load is 9.7 kN.

关 键 词：2A12铝合金 外设凸块 微观组织 断裂分析 

分 类 号：TG453.9[金属学及工艺—焊接]