Effect Of Shot Peening On Isothermal Oxidation Behavior Of Gh3535 Alloy At 900 Degrees C

The isothermal oxidation behavior of GH3535 alloy before and after shot peening at 900 degrees C was investigated by using discontinuous increasing mass method. The results show that the mass gain of the samples of the 0.45 N.mm shot peening strength is decreased by 79.7% compared to that of the unshot sample at 900 degrees C. The main oxide products of unshot GH3535 alloy are NiCr2O4, MoO2, NiMoO4; While the surface oxide film products of GH3535 alloy is composed of NiO, NiFe2O4, Cr2O3 and NiCr2O4 after shot peening treatments. Plastic deformation appears on the surface of GH3535 alloy and results in grains refinement and dislocation density increase due to shot peening. The main reason for the increase of Cr atom diffusion flux is that the dislocations and grain boundaries of the plastic deformation zone of the alloy surface act as a fast diffusion path of Cr atoms, which promotes the diffusion of Cr to the surface to form Cr-rich oxides, makes the Cr2O3 layer more quickly form, and shortens the transient oxidation period.