工艺参数对铝锂合金搅拌摩擦焊搭接接头力学性能的影响  

Effect of process parameters on mechanical properties of friction stir welded Al-Li alloy lap joints

作　　者：张丹丹[1] 曲文卿[1] 尹娜[1] 杨模聪 陈洁 孟强[3] 柴鹏[3] 

机构地区：[1]北京航空航天大学机械工程及自动化学院,北京100191 [2]上海飞机制造厂,上海200436 [3]北京航空制造工程研究所中国搅拌摩擦焊中心,北京100024

出　　处：《焊接学报》2013年第2期84-88,117,共5页Transactions of The China Welding Institution

基　　金：北京航空航天大学研究生创新实践基金资助项目

摘　　要：通过对铝锂合金搅拌摩擦焊搭接接头组织与力学性能测试,分析了不同焊接工艺参数对搭接接头拉伸性能的影响.结果表明,搅拌针的长度对接头性能影响最大,搅拌针长度从2.8 mm变为2.5 mm时,所有接头强度和塑性均有明显增加.旋转频率/焊接速度(η)对接头性能也有影响,随着η小幅度增加,接头的强度和塑性都有一定提高.在旋转频率为800 r/min、焊接速度为200 mm/min(η=4)条件下,接头的强塑性最佳,抗拉强度达到467 MPa,为母材的94%,断后伸长率为3.18%.从断口形貌观察发现,拉伸试样从前进侧搭接界面的"钩状"位置起裂,沿热影响区扩展至母材发生断裂.Through analyzing the microstructure and testing mechanical properties of friction stir welded Al-Li alloy lap joints,the effect of FSW welding parameters on the tensile properties of the lap joints was investigated.The results showed that the length of stir pin has significant influence on the tensile properties of lap joints.When the length of pin is changed from 2.8 mm to 2.5 mm,the ultimate strength and elongation of lap joints are obviously improved.Furthermore,the rotation speed / welding speed(η) also affected the performance of joints.When there was a small increasing in η,the tensile properties of lap joints increased accordingly.For the Al-Li alloy lap structure,the optimum tool rotational speed is 800 r/min,welding speed is 200 mm/min and the length of pin is 2.5 mm,the ultimate strength of lap joint reaches 467 MPa,which is equivalent to 94% that of the base metal and the elongation is 3.18%.In addition,the analysis of tensile fracture appearance indicated that the tensile cracks initiate from the location of 'Hooking' defect in the advancing side and grow along the HAZ until to the base metal.

关 键 词：搅拌摩擦焊 铝锂合金 拉伸性能 断口分析 

分 类 号：TG453.9[金属学及工艺—焊接]