Effects of laser shock peening on the surface integrity of Haynes 230 welds

Haynes 230 nickel-based superalloy is widely used in critical welded components of aeroengines and gas turbines owing to its excellent high-temperature performance. The surface integrity of the weld zone (WZ) plays a crucial role in determining the fatigue life and service reliability of these components. In this study, laser shock peening (LSP) was applied to the weld zone of Haynes 230 alloy to achieve surface strengthening by improving surface integrity. The results demonstrated that LSP induced a deep compressive residual stress exceeding −800 MPa in the surface layer of the weld and heat-affected zone (HAZ). The surface microhardness was significantly increased by 49.6%, and a strengthened layer with a thickness of 700 μm was formed. Electron backscatter diffraction (EBSD) analysis revealed significant grain refinement and a high-density dislocation structure in the surface region. The synergistic improvement of these surface integrity parameters indicates that LSP is an effective approach for enhancing the fatigue resistance of Haynes 230 welds.