Coating Effect on Improving Mechanical Property of SUS304 During High Efficiency Laser Shock Processing

摘要

Laser shock processing (LSP) employs high-energy laser pulses from a solid-state laser to create intense shock waves into a material. LSP can induce compressive residual stresses in the target and improve its mechanical property efficiency. We choose three different ablative, sacrificial coating such as black paint, aluminum foil and silica acid black paint to protect the SUS304 metal from surface melting by laser pulse, which adversely affects surface quality. This paper analyzes the effect of the paint and foil coatings on the shock wave propagation into the SUS304 specimen and the resulting change in mechanical properties versus depth. The depths of hardening by laser processing of SUS304 up to 1 mm, and the surface hardness reach to 240HV. When the laser pulse energy density increase from 2.8 GW/cm~2 to 3.6 GW/cm~2,the surface hardness of the black paint, aluminum foil and silica acid black paint increase to 34%,43%,55% respectively. And properties of the foil including its adhesion to the SUS304 were found to influence the change in surface mechanical properties.