INFLUENCE OF LASER SHOCK PEENING ON LOW- AND HIGH-CYCLE FATIGUE OF AN OT4-0 TITANIUM ALLOY

Effect of laser shock peening on the fatigue life of an OT4-0 titanium alloy is studied. Laser peening is carried out using a Q-switched Nd:YAG laser operating at a pulse repetition rate of 10 Hz. It is suggested by the analysis of the effect of various laser treatment parameters on the magnitude and distribution of residual stresses over the sample thickness that an optimal type of laser shock treatment makes it possible to create a compressive residual stress region whose depth reaches up to 1 mm and whose maximum value is 600 MPa. The results of the study of the fracture surface structure show that the fatigue fracture mechanism changes, while the service life of samples significantly increases during both low- and high-cycle fatigue after laser shock peening.