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.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
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
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
friction stir welding
mechanical behavior
fatigue property
S-N curve
fatigue fracture
