Influence of laser shock hardening on low- and high-cycle fatigue of a ОТ4-0 titanium alloy

Effect of laser shock hardening on the fatigue life of an OT4-0 titanium alloy is studied. Laser hardening is carried out using a fractionally modulated 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. It is shown by the results of studying the fracture surface structure that the fatigue fracture mechanism changes, while the service life of specimens significantly increases during both low- and high-cycle fatigue after laser shock hardening.