Surface modification of fully austenitic stainless steel SMO 254 by laser shock peening to induce compressive residual stress

The laser shock peening process was conducted with varying pulse densities on the SMO 254 material. The formation of an alpha martensitic layer from the austenitic structure was witnessed after conducting the laser shock peening process, with the migration of elements across the grains. The increase in the surface roughness value, measured by the Atomic force microscope and Mahr surface profilometer, is directly proportional to the rise in pulse density. An elevated value of compressive residual stress of -786 MPa and a higher Vickers micro hardness value of 365 HV were obtained in the specimen where a pulse density of 6000 pulse/cm(2) was applied.