Effect of Laser Shock Peening on Combined High and Low Cycle Fatigue Performance of Ti-6Al-4V Dovetail Joint

In order to investigate the effect of laser shock peening (LSP) on the combined high and low cycle (CHLC) fatigue behavior of Ti-6Al-4V alloy dovetail joint, the surface integrity characteristics and combined high and low cycle (CHLC) fatigue performance of laser shock peened Ti-6Al-4V dovetail joints were tested in this paper. The results show that compared with the as-machined (AM) specimens without laser shock peening treatment, the CHLC fatigue life of the LSP specimens increases by 729%. Laser shock peening changed the fretting wear characteristics of the contact zone of the dovetail joints. The AM specimens exhibited large-sized delamination wear pits, and microcracks were induced at the bottom of the pits and extended into the matrix. The LSP specimens showed small-sized delamination flakes. In addition, Laser shock peening also reduced the fatigue crack propagation rate of the dovetail joints. Laser shock peening can significantly improve the CHLC fatigue life, because the LSP layer changes the fatigue crack initiation mode and inhibits the early crack propagation.