Effect of laser peening on residual stress and micro-hardness of TC4 titanium alloy

Laser peening offers potential advantages over conventional peen technologies in terms of the depth of the residual stresses that can be induced, and improvements in surface micro-hardness. The present study was undertaken to understand the effect of laser penning on the properties of titanium alloy, a TC4 titanium alloy work-piece was processed with ND: YAG laser with the wavelength of 1064 nm, pulse energy of 0-10J and pulse width of 12ns, and micro-hardness and residual stress for different laser peening parameters were examined and analyzed by micro-hardness tester and X-ray diffraction. Results are presented and discussed of the residual stress profiles and the micro-hardness profiles, The experimental results show that the satisfying laser peening appearance can be achieved when the pulse energy was 6J, water tamping layer thickness was 1.8mm and ablative layer thickness was 100μm, surface micro-hardness increased by up to 33% and the compressive residual stress on the surface of laser shocked area reached up to -327.8MPa, laser peening improved hardness and residual stress of titanium alloy significantly. The experiment results show that the effect of laser peening was evidently