激光冲击强化对6061-T6铝合金TIG焊接接头疲劳性能的影响  

Influence of Laser Shock Processing on Fatigue Properties of 6061-T6 Aluminum Alloy TIG Welded Joints

作　　者：苏纯[1,2] 周建忠[1] 黄舒[1] 孟宪凯[1] 佘杰[1] 

机构地区：[1]江苏大学机械工程学院,江苏镇江212013 [2]常州工学院江苏省数字化电化学加工重点建设实验室,江苏常州213002

出　　处：《激光与光电子学进展》2015年第6期151-157,共7页Laser & Optoelectronics Progress

基　　金：江苏省自然科学基金(BK20141166);江苏省普通高校研究生科研创新计划(KYLX_1014);江苏省光子制造科学与技术重点实验室开放基金(GZ201305)

摘　　要：利用高功率高重复率的Nd∶YAG激光对6061-T6铝合金钨极弧焊(TIG)焊缝和热影响区进行冲击强化处理,通过调整激光能量、冲击区域,进行了对比试验。通过低循环大应力拉伸疲劳测试获得了未处理和激光冲击强化后的焊接接头试样的安全寿命,分析了激光冲击强化对铝合金焊接接头疲劳性能的影响,根据断口形貌扫描电子显微镜(SEM)和X射线能谱分析(EDS),残余应力和硬度测试结果,研究了激光冲击强化提高焊接接头抗拉疲劳性能的微观机理。结果表明,激光冲击强化使6061-T6铝合金焊接接头安全寿命提高117.1%,其中激光能量为5 J、冲击区域为18 mm×16 mm,双面冲击后接头试样获得最大疲劳寿命。同时激光冲击强化抵消了接头表面残余拉应力并产生残余压应力,显著提高接头硬度,影响深度约1.4 mm。The surface of 6061-T6 aluminum alloy welding line and heat-affected zone by tungsten inert gas （TIG） is processed by high power and high repetition-rate Nd ： YAG laser. The contrast test is completed through adjusting the parameters of laser energy and laser shock processing （LSP） path. The safety lives of welded joint specimens with and without LSP are estimated by making low cycle tensile fatigue test. The effect of LSP on fatigue properties of aluminum alloy welded joint is analyzed. The fatigue fracture mechanisms of these specimens with and without LSP are studied by fracture surface, scanning electron microscope （SEM） energy dispersive spectrometer （EDS）, residual stress and hardness analysis. The result show that the safety life of 6061-T6 aluminum alloy welded joints is increased 117.1%. The welded joint specimen which has the longest fatigue life is processed by LSP with laser energy 5 J, shock area 18 mm× 16 mm and double shock. Compressive residual stress is induced at the surface of welded joints by LSP. The hardness of welded joints are significantly improved after LSP.

关 键 词：光学制造 激光技术 激光冲击强化 铝合金 焊接接头 低周疲劳 残余应力 

分 类 号：TG404[金属学及工艺—焊接] TN249[电子电信—物理电子学]