Abstract:

Fatigue performances of resistance spot welds of aluminum alloy 5754 and 6111-T4 were experimentally investigated. Fatigue data of various specimen geometries were generated. Fatigue failure modes of aluminum spot welds were studied and fatigue crack growth behaviors were explored. Fatigue results indicate that effects of base material on joint fatigue life are negligible. To some extent,fatigue life increases as cyclic load ratio decreases. Fatigue life of spot welded specimen highly depends on the nature of load types at spot weld. In product design and development phases, spot weld under pure peel load should be avoided properly.

Key words: aluminum alloy, resistance spot welding, fatigue analysis, fatigue failure analysis

摘要：

研究了铝合金AA5754和AA6111-T4焊点的疲劳性能,获得了不同厚度及试件类型的焊点疲劳数据;研究了试件类型不同时焊点的疲劳失效模式,讨论了焊点疲劳裂纹的扩展形式;分析了铝合金焊点疲劳寿命的影响因素。结果表明:焊点疲劳失效模式主要有两种,分别是母材“眉状”裂纹断裂和焊点熔核界面断裂;母材对焊点疲劳寿命影响不大;循环载荷比对焊点寿命有一定的影响,增大载荷比导致焊点疲劳寿命略有下降;试件类型对焊点寿命有很大的影响,应在设计中避免焊点承受剥离载荷。

关键词: 铝合金, 电阻点焊, 疲劳性能, 疲劳失效分析