We prepared three kinds of Ni based alloy cladding coatings on 316L stainless steel at different power levels. The microstructure of the cladding layer was observed and analyzed by XRD, metallographic microscope, and SEM. The hardness of the cladding layer was measured, and the wear resistance of it was tested by a friction instrument. The results show that the effect of laser cladding is good, and it has good metallurgical bonding with the substrate. Different microstructures such as dendritic and equiaxed grains can be observed in the cladding layer. With the increase in laser power, more equiaxed and columnar dendrites can be observed. The phase composition of the cladding layer is mainly composed of γ–Ni solid solution and some intermetallic compounds such as Ni₃B, Cr₅B_3, and Ni₁₇Si₃. The results of EDS show that there are some differences in the distribution of C and Si between dendrites. The hardness of the cladding layer is about 600 HV_0.2, which is about three times of the substrate (~200 HV_0.2). Through the analysis of the wear morphology, the substrate wear is serious, there are serious shedding, mainly adhesive wear, and abrasive wear. However, the wear of the cladding layer is slight, which is abrasive wear, and there are some grooves on the surface.

In order to improve fatigue life of GH3039 superalloy, GH3039 superalloy sheets were treated by laser shock peening (LSP). The microstructure of GH3039 superalloy before and after LSP was characterized using an optical microscope, transmission electron microscope (TEM), and X-ray diffractometer. The fatigue life of the samples with and without LSP was investigated by fatigue experiments. Moreover, surface profile and residual stress were also examined. Experimental results indicated that the grains in the surface layer of the LSP sample were remarkably refined and reached the nanometer scale. The average surface roughness increased from 0.024 μm to 0.19 μm after LSP. The average fatigue life of the laser treated samples was 2.01 times larger than that of the untreated specimens. Additionally, mathematical statistical analysis confirms that LSP has a significant influence on the fatigue life of GH3039 superalloy. The improvement of fatigue life for the laser processed GH3039 superalloy was mainly attributed to compressive residual stress and grain refinement generated by LSP.

Effects of laser shock processing (LSP) on the cavitation erosion resistance of laser weldments were investigated by optical microscope (OM), scanning electron microscope (SEM) observations, roughness tester, micro hardness tester, and X-ray diffraction (XRD) technology. The morphological microstructures were characterized. Cumulative mass loss, incubation period, erosion rate, and damaged surface areas were monitored during cavitation erosion. Surface roughness, micro-hardness, and residual stress were measured in different zones. Results showed that LSP could improve the damage of morphological microstructures and mechanical properties after cavitation erosion. The compressive residual stresses were generated during the process of LSP, which was an effective guarantee for the improvement of the above mentioned properties.

This paper is based on laser shock peening (LSP) system with a flat‐topped beam, using robot simulation software to determine the oblique shock angle of different areas of a certain turbine disk mortise. Three‐dimensional finite element analysis was used to study residual stress field of Ni‐based alloy GH4169 under flat‐topped laser oblique shocking. The effects of different laser energy and different shocking number on residual stress field of Ni‐based alloy GH4169 of LSP were studied. Three‐dimensional finite element analysis used super‐Gaussian beam distribution to construct spatial distribution model of shock wave induced by LSP. The simulation results were in good agreement with the experimental results. The research results will provide a theoretical basis for LSP of certain turbine disk mortise.

Aiming at the phenomenon that the residual stress induced by Laser Shock Peening (LSP) will relax and redistribute under various loads, temperature, cyclic load, and the dual treatment of temperature and cyclic load on the residual stress relaxation of FGH95 powder superalloy after LSP treatment were studied, and the analysis model of relevant residual stress relaxation was constructed. The purpose is to understand the strengthening effect and stability of the alloy under temperature and cyclic load after LSP treatment. With the increase of treatment temperature, the relaxation of residual stress became more and more obvious. Most of the residual stress relaxation occurred in the first 30 min of temperature treatment, then slowed down and stabilized after 1 h. The residual stress was initially relaxed in the first 50 cycles, remained roughly unchanged between 50 and 5000 cycles. The intensify of the cyclic load increasing, adding material yield level, further plastic deformation and residual stress relaxation rate increases. With the increase of load intensify and load ratio, residual stress relaxation was also increased. The residual stress relaxation rate after 600 °C and cyclic load treatment was 56.2%, both greater than that after 600 °C or cyclic treatment of 25 °C, but less than the sum of the two conditions. The results of this paper provide a reference for the LSP of the FGH95 powder superalloy turbine disk and other aero engine parts.