Laser shock wave-induced enhanced thermal corrosion resistance of Ti6Al4V alloy fabricated by laser powder bed fusion

In this study, the effect of laser shock peening (LSP) on the microstructural evolution and thermal corrosion behaviors of laser powder bed fusion processed (LPBFed) Ti6Al4V samples was characterised in Na2SO4 + NaCl mixed solutions at 500 degrees C, 600 degrees C and 700 degrees C. Thermal corrosion resistance was evaluated using thermo-kinetic curves, thermal corrosion products, and corrosion morphology. The results indicated that the thermal corrosion layer of the LSPed samples was thinner and denser than that of the LPBFed samples, and the mass gain of the LSPed samples was significantly reduced, suggesting a better thermal corrosion resistance. This is attributed to the refined grains, high-density dislocations, and nano-twins. Finally, the improvement mechanism of LSP on the thermal corrosion resistance of the LPBF-treated Ti6Al4V titanium alloy was revealed.