Microstructure and Hot Corrosion of GH2036 Alloy Treated by Laser Shock Peening

The effects of laser shock peening (LSP) on the microstructure, residual stress, microhardness and hot corrosion of GH2036 alloy at high temperature (700 degrees C) were investigated by transmission electron microscopy, x-ray diffraction, Vickers hardness testing and scanning electron microscopy, respectively. The results show that many crystal defects and precipitate phases were induced by LSP. The maximum surface residual compressive stress and micro-hardness of the LSP-treated sample with 9 J of pulse energy were 520 MPa and 275 HV, respectively. The hot corrosion kinetics of GH2036 showed that the sample treated with 9 J of pulse energy recorded the lowest mass loss (3.85 mg/cm(2)) compared to the untreated sample (11.35 mg/cm(2)). Higher crystal defects provided the diffusion channels of elements (Fe, Cr, etc.), which facilitated the formation of a denser and more homogeneous oxide layer compared to untreated samples. In addition, the spallation of the oxide layer was obviously alleviated after LSP.