搅拌摩擦焊接接头的静载力学行为和疲劳特性  

Mechanical Behavior and Fatigue Properties of Joints by Friction Stir Welding

作　　者：王快社[1] 王训宏[1] 沈洋[1] 徐可为[2] 胡锴[3] 

机构地区：[1]西安建筑科技大学,陕西西安710055 [2]西安交通大学,陕西西安710049 [3]西安航空发动机(集团)有限公司,陕西西安710021

出　　处：《稀有金属材料与工程》2007年第9期1588-1591,共4页Rare Metal Materials and Engineering

基　　金：陕西省科技计划项目(2003K07-G8);西安市工业攻关项目(GG04063)资助

摘　　要：对LF2铝合金搅拌摩擦焊接接头的静载力学行为和疲劳特性进行了研究，建立了焊接接头的孓Ⅳ曲线。力学实验结果表明：LF2铝合金搅拌摩擦焊接接头的最高抗拉强度为252．8MPa，是母材抗拉强度的95．4％。疲劳实验结果表明：搅拌摩擦焊接接头表现出良好的疲劳性能，疲劳寿命N=10^5次的疲劳强度为59～65MPa。显微组织分析表明：搅拌摩擦焊接接头具有细小的等轴晶粒和狭窄的热影响区，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：随着驻留滑移带的扩展逐渐萌生裂纹，在交变应力作用下最终导致失效。Mechanical behavior and fatigue properties of the LF2 aluminum joints by friction stir welding （FSW） were studied and the S-N curve of joints were established. The results show that the maximum tensile strength is 252.8 MPa, showing an excellent fatigue properties for FSW welded joints, which is 95.4% of that of the base metal. The fatigue strength was determined to be 59-65 MPa for the fatigue life of N=106 cycles. The microstructure of joints showed comparatively fine equiaxed grains and a narrow heat affecting zone in the FSW welds, which inhibit the growth of crack and produce a long fatigue life. The fracture morphologies also show that the fatigue fracture occurred under alternating stress with the development of persistent slip bands.

关 键 词：搅拌摩擦焊接 力学行为 疲劳性能 S-N曲线 疲劳断口 

分 类 号：TG407[金属学及工艺—焊接]