Influence of surface modifications by laser shock processing on the acid chloride stress corrosion cracking susceptibility of AISI 304 stainless steel

The effects of laser shock processing (LSP) on stress corrosion cracking (SCC) behavior of AISI 304 stainless steel have been investigated using slow strain rate tests (SSRT) in acid chloride solution. Modifications of surface microstructure are characterized by scanning electron microscopy (SEM) and transmission electron microscope (TEM). Results show that LSP generate deformation twins and refined microstructures in the surface layer of AISI 304 stainless steel. Results of SSRT tests reveal that significant improvements in stress corrosion cracking (SCC) resistance are observed in acid chloride solution. These improvements have been attributed to surface microstructure changes and compressive residual stress induced by LSP. The results confirm that the application of LSP is of a practical option to improve SCC resistance of AISI 304 stainless steel.