下扎深度对7075铝合金搅拌摩擦点焊接头组织和性能的影响  

Effect of Plunge Depth on Microstructure and Properties of Friction Stir Spot Welded Joints of 7075 Aluminum Alloy

作　　者：俞宗华[1] 张大童[1] 张文[1] 邱诚[1] 罗锡才 YU Zonghua;ZHANG Datong;ZHANG Wen;QIU Cheng;LUO Xicai(Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic Materials,South China University of Technology,Guangzhou 510641,China;Electrical and Mechanical Engineering Department,Guangzhou Railway Polytechnic,Guangzhou 510430,China)

机构地区：[1]华南理工大学广东省金属新材料制备与成形重点实验室,广东广州510641 [2]广州铁路职业技术学院机电工程学院,广东广州510430

出　　处：《热加工工艺》2020年第5期41-45,48,共6页Hot Working Technology

基　　金：广东省科技计划项目(2015B090926004).

摘　　要：对3 mm厚的7075-T6铝板进行搅拌摩擦点焊试验,研究下扎深度对接头组织和力学性能的影响。结果表明,搅拌区晶粒得到极大细化和均匀化,它的晶粒尺寸随下扎深度的增加而逐渐增大。随着下扎深度增加,接头畸变高度和畸变角度先减小后增大,变形区宽度先增大后减小,下扎深度为5.1 mm时,它的有效结合区宽度及变形区宽度最大,畸变高度和畸变角度最小。接头的拉剪载荷随下扎深度的增加先增大后减小,下扎深度5.1 mm的接头获得最大的拉剪载荷值,为12.44 kN,同时它的焊点表面成形良好,结合程度最佳。接头在拉伸试验中的失效方式为韧-脆混合型断裂。Friction stir spot welding tests were carried out on 3 mm-thick 7075-T6 aluminum alloy sheet, and the influence of different plunge depths on the microstructure and mechanical properties of joints was studied. The results show that grains in the stirred zone are greatly refined and homogenized, and the grain size increases gradually with the increase of the plunge depth. With the plunge depth increasing, the distortion height and distortion angle first decrease and then increase, while the width of the deformation zone first increase and then decrease. When the plunge depth is 5.1 mm, the width of effective bonding zone and deformation zone of joint are the largest, and the distortion height and angle are the smallest. The tension-shear load of the joint increase first and then decrease with the increase of the plunge depth. When the plunge depth is 5.1 mm, the maximum tension-shear load of the joint is obtained,which is 12.44 kN. At the same time, the surface of the joint is well formed and the bonding is the best. The fracture mechanism of the joints in the tensile tests is ductile-brittle mixed fracture.

关 键 词：7075铝合金 搅拌摩擦点焊 下扎深度 微观组织 力学性能 

分 类 号：TG453.9[金属学及工艺—焊接]