Effect of Warm Laser Shock Peening on Microstructure and Properties of GH4169 Superalloy

In order to explore the effect of warm laser shock peening (WLSP) on the GH4169 superalloy, the microhardness, residual stress, and microstructure of the samples are compared and analyzed by laser shock peening (LSP) at 24 °C and WLSP at 200 °C, 250 °C, and 300 °C. The results show that the microhardness level and hardened layer thickness increase gradually with the increase of process temperature. Compared with LSP (24 °C), WLSP (300 °C) increased the maximum microhardness of the sample by 13.0% and the depth of hardened layer increased by 25.0%; The influence of process temperature has little effect on the residual stress level, and the residual stress difference of the samples after LSP (24 °C) and WLSP (200 °C, 250 °C, 300 °C) are within 40MPa; Compared with the microstructure of the original sample, the dislocation density of the samples after LSP and WLSP increased significantly, compared with LSP (24 °C), the number of slip line projections after WLSP (300 °C) is more, the size is larger, and there are a lot of dislocations tangled around the precipitates. This study shows that WLSP has a better strengthening effect than LSP. (paper)