Residual Stress Distribution and Elevated Temperature Fatigue Behaviour of Laser Peened Ti-6Al-4V with a Curved Surface

Abstract The influence of laser shock peening without coating (LPwC) on the induced compressive residual stress and the fatigue behaviour (R = −1 at 300 °C) was investigated on curved samples of Ti-6Al-4V. The stress relaxation after fatigue was also examined. In the peened samples crack initiation shifted to a depth of ∼ 200 μm, with 3 fold increase in fatigue life at 400 MPa. Decrease in fatigue striations in the laser peened (331.48 nm/cycle) samples compared to unpeened (410.54 nm/cycle) samples indicated retardation of crack propagation rate. Further, the effect of grain refinement and misorientation angles on fatigue behaviour is also considered.