铜铝异种材料搅拌摩擦焊接头组织和力学性能分析

Analysis of microstructure and mechanical properties of friction stir welded joint of Cu/Al dissimilar materials

采用两种搅拌摩擦焊工艺对铜-铝异种材料(1060-O铝合金、T2紫铜)对接接头进行焊接。采用金相组织观察、显微硬度测定、拉伸试验及SEM断口扫描等方法,研究了两种不同旋转速度对铜-铝异种材料接头的微观组织和力学性能的影响,并分析了断口微观形貌。结果表明,铜-铝异种FSW接头横截面形貌表现出两种金属相互穿插混合的特征,接头焊核区铝合金基体中弥散分布着铜合金粒子,接头焊核区两种金属结合的界面处形成铝铜金属间化合物。较高转速的铝-铜焊接接头焊核区铜的嵌入层深度更大,铝侧热机影响区组织受到的搅拌作用更加剧烈,晶粒被拉长和扭转更明显。较高转速的铝-铜接头力学性能优于低转速接头,具有高的接头硬度和抗拉性能。

The butt joints of dissimilar materials(1060-O aluminum alloy,T2 copper)were welded by two kinds of friction stir welding.The effects of two different rotation speeds on the microstructure and mechanical properties of the joint were studied by means of metallographic observation,microhardness test,tensile test and SEM fracture scanning,and the microstructure of fracture was also analyzed.The results show that the cross section macromorphology of the dissimilar FSW joint is characterized by the interpenetrating and mixing of the two base metals.The copper alloy particles are dispersed in the aluminum alloy matrix in the nugget zone(NZ),and the aluminum copper intermetallic compound(IMC)forms at the interface of the two metals in the NZ.The embedded layer depth of copper in the NZ of higher-speed aluminum copper welding joint is larger,the microstructure of the TMAZ on the aluminum side is stirred more violently,and the grains are elongated and twisted more obviously.The mechanical properties of high-speed joints are better than those of lower-speed joints,which have higher joint hardness and tensile properties.