Effect of high frequency impacting and rolling on fatigue crack growth of 2A12 aluminum alloy welded joint

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.

Automated summary

The research results indicate that HFIR treatment can refine the grain sizes on the surface of welded joints and increase the hardness, elastic modulus, and residual stress, effectively extending the fatigue crack growth life of welded joints.