Strain rate correspondence of fracture surface features and tensile properties in AISI304 stainless steel under different LSP impact time

Ductile fracture behaviors of AISI304 stainless steel were investigated under different LSP impact time when the strain rate varied from 1×10−4s−1 to 0.1s−1 during the tensile test. It can be found that both the applied strain rate and the LSP impact time had strong influences on the ultimate tensile strength (UTS), the flow stress and fracture morphology of AISI304 stainless steel. On the one hand, the UTS and the flow stress increased with increasing strain rate, and the dominated fracture feature changed from microvoid coalescence at the lower strain rates to equiaxed dimple with smaller diameter at the higher strain rates. On the other hand, LSP can enhance the UTS and the flow stress of AISI304 stainless steel, and the ductile dimples in the fracture surface of the treated sample became smaller, shallower and more uniform with increasing LSP impact time. In addition, the influence mechanism of strain rate and LSP impact time on fracture surface was also analyzed and discussed.