Tribological Performance of Laser Shock Peened Cold Spray Additive Manufactured 316L Stainless Steel

Abstract

In recent years, cold spray additive manufacturing (CSAM) has become an attractive technology for surface modification and protection. However, due to the intrinsic porous nature of CSAM coatings, they suffer from rapid material degradation due to premature brittle fracturing induced by tribological interactions. In this work, laser shock peening (LSP) was utilized as a post-processing technology to mitigate the surface porosity and augment the surface characteristics of CSAM 316L stainless steel (SS). Due to the synergistic influence of severe plastic deformation and rapid surface heating, the surface porosities were effectively healed, thus reducing the surface roughness. Combined with the surface-strengthening effects of LSP, the frictional resistance and transfer layer formation on the CSAM LSP surfaces were reduced. The underlying mechanisms for these findings were discussed by correlating the atomic, microstructural, and physical features of the LSP surfaces. Based on these findings, it can be suggested that LSP is indeed a useful technique to control the surface characteristics of CSAM 316L SS coatings.