7050-T7451铝合金搅拌摩擦焊接头低周疲劳性能研究  

Investigation on Low-cycle Fatigue Properties of Friction Stir Welding Joints of 7050-T7451 Aluminum Alloy

作　　者：王希靖[1] 张杰[1] 牛勇[1] 李树伟[1] 徐成[1] 

机构地区：[1]兰州理工大学甘肃省有色金属新材料国家重点实验室,甘肃兰州730050

出　　处：《热加工工艺》2008年第13期6-8,20,共4页Hot Working Technology

基　　金：国家自然科学基金资助项目(10577010)

摘　　要：对航空用5mm厚铝合金7050-T7451搅拌摩擦焊接头的低周疲劳性能进行了研究。在合适的焊接工艺参数及良好的焊接接头的基础上,进行了焊接接头的低周疲劳实验,得到了低周疲劳寿命表达式和应变-寿命曲线。用扫描电镜观察了疲劳断口的微观形貌并分析了疲劳断裂机理。结果表明:裂纹在接头底部启裂,沿前进侧热机影响区与焊核区的交界处扩展至断裂;试样在高应变下循环硬化和软化现象不明显;较低应变时有循环软化倾向。The low-cycle fatigue properties of friction stir welding joints of-5 mm thick aluminum alloy 7050-T7451 used for aero field were investigated based on proper welding parameters. The expression of the lowcycle fatigue life and the curves of strain-life were obtained. The fractography of fatigue specimens were examined by SEM and the mechanism of fatigue fracture was analyzed. The results show that the fatigue cracks initiate from the root of the welds, and then propagate to fracture along the boundary between the TMAZ（thermo-mechanically affected zone） in the advancing side and the weld nuclear zone. The circulatory hardening and softening phenomenon of the sample is not obvious in high strain condition, but it has circulatory softening tendency in low strain condition.

关 键 词：搅拌摩擦焊 7050-T7451铝合金 低周疲劳 断口形貌 

分 类 号：TG453[金属学及工艺—焊接]