中文摘要：

为了探讨2219-T6铝合金搅拌摩擦焊接头疲劳断裂位置与区域局部力学性能及材料微观结构之间的关系,对铝合金2219-T6搅拌摩擦焊接头开展了疲劳试验研究.试样接头疲劳断裂处大多位于焊核区与热机区交界处及临近区域,在裂纹萌生处的亚表面发现有大的夹杂.焊核区有明显微空洞,小角度晶界最多.利用ABAQUS软件数值模拟接头疲劳,分析了接头局部区域力学性能.接头的热机区和焊核区的主应变值较大,这些区域较其他区域更易萌生疲劳裂纹.

英文摘要：

Fatigue tests were performed on the friction stir welded joints of 2219-T6 aluminum alloy in order to research the relationship between the locations of fatigue fracture of 2219-T6 aluminum alloy friction stir welded joints and local mechanical properties and microstructure. The fracture locations were mostly in the junction of the nugget and the thermal mechanical affected zones and adjacent areas. Big impurities were found in the subsurface of the location of the crack initiation. The obvious micro-void and the maximum amount of low angle grain boundary were found in the nugget. In order to obtain the local mechanical properties of the welded joints,the numerical simulation under fatigue loading for the welded joints was conducted with ABAQUS software. The result shows that principal strain values in thermomechanical and nugget zones are bigger than that in other zones. It easily initiates the fatigue cracks in these zones than in others.