2024铝合金搅拌摩擦焊接头的疲劳性能  

Study on Fatigue Properties of Aluminum Alloy 2024 Joint by Friction Stir Welding

作　　者：王希靖[1] 牛勇[1] 张杰[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省部共建国家重点实验室,甘肃兰州730050

出　　处：《热加工工艺》2008年第15期4-5,9,共3页Hot Working Technology

基　　金：国家自然科学基金资助项目(10577010)

摘　　要：对2024铝合金搅拌摩擦焊接头的疲劳特性进行了研究,建立了接头的S-N曲线。疲劳试验结果表明,搅拌摩擦焊接头表现出良好的疲劳性能。搅拌摩擦焊接头具有细小的等轴晶组织和狭窄的热影响区,阻碍了滑移带的形成和裂纹的扩展,从而提高了接头的疲劳性能。疲劳断口分析显示,裂纹在接头底部启裂,通过位错的塞积作用使得滑移带扩展逐渐萌生裂纹,在交变应力的作用下最终断裂。The fatigue properties of aluminum alloy 2024 joint by friction stir welding were investigated and the S-N curve was obtained. The test results show that the joint by friction stir welding has good fatigue performance. The improvement of fatigue properties of the joint is attributed to exiguous equiaxial crystalline structure and constrictive heat-affected zone, which restricts the formation on glide band and the expansion of cracks. The analysis on fatigue fracture mechanism show that the fatigue crack initiates from the root of the welds, the expansion of glide band gradually formates cracks through cramming of dislocation, and eventually fractures through alternating stress.

关 键 词：搅拌摩擦焊 疲劳性能 S-N曲线 断口形貌 

分 类 号：TG453[金属学及工艺—焊接]