搅拌摩擦焊工艺参数对纯铜接头组织和力学性能的影响  

Effect of processing parameters on microstructure and mechanical properties of pure copper joints made by friction stir welding

作　　者：李夏威[1] 张大童[1] 邱诚[1] 张文[1] 

机构地区：[1]华南理工大学国家金属材料近净成形工程技术中心,广州510640

出　　处：《焊接学报》2011年第9期93-96,117-118,共4页Transactions of The China Welding Institution

基　　金：中央高校基本科研业务费专项资金资助项目(2009ZM0264);广州市科技支撑计划资助项目(2009Z2-D811)

摘　　要：研究了搅拌摩擦焊工艺参数对3 mm的纯铜板材焊接接头组织和力学性能的影响.结果表明,在搅拌头旋转频率固定为800 r/m in,焊接速度在60~300 mm/m in范围内均得到了外表面美观、内部无缺陷的接头.焊接接头由两边向中间依次由母材区、热影响区、热力影响区和搅拌区组成.搅拌区组织由于动态再结晶作用使得该部分区域得到了明显的细化,硬度曲线呈近似＂U＂形,搅拌区硬度低于母材.搅拌区晶粒尺寸随着焊接速度的增大不断减小.在焊接速度为100 mm/m in时,接头综合力学性能达到最佳,抗拉强度达到282.5 MPa,断后伸长率达到21.7%,分别为母材的93.8%和79.2%.拉伸断口SEM图像显示焊接速度为300 mm/m in条件下得到的接头为脆性断裂,而其它参数下得到的接头断裂形式和母材类似,断口处存在韧窝和撕裂棱,为韧性断裂.The main objective of this investigation was to apply friction stir welding(FSW) for joining of pure copper plate which is 3 mm thick.Defect free welds were obtained at a constant rotation speed of 800 r/min and travel speed ranging from 60 mm/min to 300 mm/min.The influence of welding parameters on the microstructure and mechanical properties of the pure copper joints were investigated.The joints exhibit four distinct zones,parent material,heat affect zone,thermo-mechanically affected zone,and stir zone respectively.Microstructure of the stir zone consists of fine equiaxed grains due to dynamic recrystallization,the average grain size of the stir decreased with the increasing of welding speed.Microhardness distribution curve showed a'U'shape,and the hardness of the stir zone was lower than that of the parent material.The tensile strength and elongation of the joints reached about 285 MPa and 21.7% at a travel speed of 100 mm/min,which were 93.8% and 79.2% of the parent material,respectively.SEM indicated that the joint formed at the 300 mm/min failed in a brittle fracture manner and joints formed with other parameters failed in a ductile fracture manner.

关 键 词：搅拌摩擦焊 纯铜 组织 力学性能 

分 类 号：TG453[金属学及工艺—焊接]