The investigation of laser shock peening effects on corrosion and hardness properties of ANSI 316L stainless steel

Abstract

Laser shock peening (LSP) is known as a post processing surface treatment which can improve the mechanical properties of some materials. Shock-waves are generated by confining the laser-induced plasma to cause a large pressure shock wave over a significant surface area. In the present study, effects of LSP on the electrochemical corrosion and micro hardness properties of 316L stainless steel alloy was investigated by changing the laser parameters such as the laser spot size, the average number of impacts and the laser intensity. Since laser parameters do not cover the desired region of LSP, we have to use the proper design of experiment method, in which the D-optimal design of MATLAB was selected. Results revealed that by increase in irradiance, number of impacts and spot size of laser beam, improvement in the surface micro hardness and corrosion resistance is achieved. Also due to unexpected drop into the outcome of our experiments, it was found that the contamination of the transparent overlay and reduction of the absorption coefficient of the absorbent layer, plays a key role to reduce the efficiency of the mechanical impacts. So by changing the experimental conditions, even better results are expected.