Correlation between the changes in microstructure and chemical composition of the surface layer of nickel superalloy after laser shock processing

Abstract

The aim of this work was to investigate the correlation between the changes in microstructure and chemical composition of the surface layer of nickel superalloy after Laser Shock Processing. It has been shown that overlapping of subsequent laser shots causing the surface roughness, which values are much smaller in the direction of overlapping of subsequent shots than in the direction perpendicular to. After the LSP process we can distinct in the surface layer following zones: melted, recrystallized, highly deformed and partially deformed zone. Due to the thermomechanical deformation, there are significant changes in the microstructure and elements distribution in the subsurface areas. The distribution of chemical elements in the melted and recrystallized zones is more homogeneous than in deformed and partially deformed ones, which is due to the disappearing, distortion and refinement of the regular gamma/gamma ' cell structure.