(中南大学 高性能复杂制造国家重点实验室，长沙 410083)
摘 要: 采用搅拌摩擦焊方法实现T2紫铜和不锈钢异种金属的焊接，得到外观成形良好、变形小的搭接接头。通过金相、能谱扫描分析焊接接头组织。结果表明：紫铜−不锈钢搭接接头后退侧塑性较好的紫铜金属材料从上往下流动形成层状流线，在焊缝交界处与塑性较差的不锈钢金属材料形成具有模糊界线的区域组织；焊核区上表面组织为细小的等轴晶，紫铜侧组织由于受高温时间较长，为粗大的等轴晶，钢侧组织受搅拌针端部作用形成再结晶晶粒，交界处出现涡流交迭形状；前进侧有两种组织形貌，即铜基混合条带和钢基混合条带；紫铜−不锈钢异种材料焊接时在不锈钢侧存在搅拌头磨损后脱落的元素成分。
关键字: T2紫铜；不锈钢；搅拌摩擦焊；搭接接头；显微组织
（State Key Laboratory of Complicated Equipment Design and Extreme Manufacturing,
Central South University, Changsha 410083, China）
Abstract:The dissimilar metals of copper (T2) and stainless steel (304) were jointed by friction stir welding (FSW), and the lap joints with good appearance, small deformation were obtained. The microstructure of welded joint was studied by optical microscopy and energy disperse spectroscopy (EDS). The results show that the copper metal with good ductility of the retreating side in the lap joint flows from top to bottom, forms layered streamline. In the interfacial region, regional organizations with vague boundaries are generated with stainless steel metal, which has poor plasticity. On the surface in nugget, the organization shows fine equiaxed grain, the copper side in nugget shows coarse equiaxed grain due to the long high temperature, while the stainless steel side in nugget shows the recrystallization grains originated from the effect of the pin end, and the organization in the juncture shows eddy overlap shape. The organization in advanced side has two morphologies: hybrid striped strap based on steel and hybrid striped strap based on copper. In copper and stainless steel welding process, there are some element worn from the pin tool in the stainless steel base metal.
Key words: T2 copper; stainless steel; friction stir welding; lap joint; microstructure
