The synergetic effects of shot peening and laser-shot peening on the microstructural evolution and fatigue performance of a medium carbon steel

The synergetic effect of shot peening (SP) and laser shot peening (LSP) on the fatigue behavior of a medium carbon steel was investigated. A fatigue life transition was observed in the S-N curve, where the fatigue per-formance of the SP + LSP specimen was improved only at lower stress levels. This result is consistent with the short crack propagation behavior observed in the near-threshold region. The heterogeneous structures comprised by ultra-fine grains, dislocation tangles, and more high-angle grain boundaries were responsible for this behavior which effectively retard the short crack propagation.

Automated summary

The synergetic effect of shot peening and laser shot peening on the fatigue behavior of a medium carbon steel was studied. The fatigue performance of the SP + LSP specimen was found to be improved only at lower stress levels, which is consistent with the observed short crack propagation behavior near the threshold region. The heterogeneous structures of ultra-fine grains, dislocation tangles, and high-angle grain boundaries were responsible for effectively retarding the short crack propagation.