Improving Fatigue Performance of Equiaxed TC4 Titanium Alloy by Compound Shot Peening

First equiaxed TC4 titanium alloy fatigue specimens were treated with high energy shot peening for different time to prepare a certain depth of nano-surface layer, and then the nano-surface quality of the specimens were improved by compound shot peening using small size shots. Finally fatigue test was done to specimens with defferent shot peening state. The results show that after compound shot peening, fatigue strength of the equiaxed TC4 titanium alloy increased by 34% compared to that of material in un-shot peening state, and increased by 12% compared to that of materia in pure high energy shot peening state. High energy shot peening restrained the effect of surface nanocrystallization improving fatigue strength of TC4 titanium alloy, and the compound shot peening could repair the high energy shot peening injuries partly.