Hot corrosion behavior of TC11 titanium alloy treated by laser shock processing

The aim of this research is to improve the hot corrosion resistance of TC11 titanium alloy by laser shock processing. Specimens were treated by laser shock processing on the whole surface. The hot corrosion resistance beneath Na2SO4 containing 20 wt.% NaCl salt deposits at 650 °C, 800 °C and 900 °C in air was investigated. The effects of LSP impacts on surface microstructure, residual stress, and microstructure after hot corrosion were investigated by transmission electron microscope, X-ray diffraction technology, and scanning electron microscope. Results show that laser shock processing can induce −295 MPa compressive residual stresses. The microstructure after LSP was characterized by a high amount of twins and highly tangled and dense dislocation arrangements. We even observed nano-crystallization. More protective oxidation films were remained on the surface of laser shocked specimens after hot corrosion, and it mainly consists of TiO2, Al2O3, MoO3, etc. The average corrosion rate of TC11 titanium alloy treated by laser shock processing is more than 50% lower than that of the untreated alloy.