The influence of high frequency impacting and rolling (HFIR) on fatigue crack growth (FCG) of welded joint were researched. Results showed that grain sizes of the top surface of BM and WS were refined; Both the nanomicrohardness, elastic modulus and maximum compressive residual stress (CRS) were increased. The introduction of near-surface CRS leads to obvious changes of the surface actual stress situation, increases the crack closure and decreases the stress intensity factor of crack tip. FCG life of BM and WS increased by 1.594~1.744 times and 2.902~3.231 times. BM and WS exhibited a different fracture characterized before and after HFIR.

中文翻译：

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高频冲击轧制对2A12铝合金焊接接头疲劳裂纹扩展的影响

研究了高频冲击和滚动（HFIR）对焊接接头疲劳裂纹扩展（FCG）的影响。结果表明，BM和WS顶面的晶粒细化。纳米显微硬度，弹性模量和最大压缩残余应力（CRS）均增加。近表面CRS的引入导致表面实际应力状况发生明显变化，增加了裂纹闭合并降低了裂纹尖端的应力强度因子。BM和WS的FCG寿命分别增加了1.594〜1.744倍和2.902〜3.231倍。BM和WS在HFIR前后表现出不同的断裂特征。