Improving the Surface Properties of Ti6Al4V with Laser Shock Processing
Cesar A. Reynoso-Garcia, G. Gomez-Rosas, O. Blanco, C. Rubio-Gonzalez, A. C. Chavez, E. Castañeda and J. L. Ocana
Laser shock processing (LSP) is a technique that induces residual compressive stresses in metallic objects through the plastic deformation caused by the propagation of shock waves generated by laser pulses. The alloy Ti6Al4V is utilized in various industries such as the aerospace, automotive, and medical industries. In this study, LSP was performed using a high-power, low-cost, Q-switched Nd:YAG pulsed laser that emits at two wavelengths, 1064 and 532 nm, with pulse times of 6 and 5 ns, respectively. Power densities of 8.4 and 7.5 GW/cm2 were tested. The material had no protective layer on the surface but was covered with a thin film of water (LSPwC). At both power densities, LSP produced great depth and magnitude residual compressive stresses (a result not previously reported), a reduction in the friction coefficient, and an increase in the hardness were found. The results obtained with both wavelengths were satisfactory and improved the surface properties of Ti6Al4V.
Keywords: LSP, coefficient of friction, Ti6Al4V, residual stress, hardness, Nd:YAG laser