Influence of surface plastic deformation on oxidation behavior for low Cr content nickel superalloy: Focus on the Cr diffusion.

The surface plastic deformation induced by shot-peening on the oxidation behavior for GH3535 alloy was investigated. The variation in microstructure and mechanical property of GH3535 with different shot peening intensities was compared, followed by exposure to air at 950 °C for 200 h. The structure and elemental distribution of the oxide film were analyzed by combining SEM, EBSD and TEM. The result shows that shot peening significantly improves the oxidation resistance of GH3535 alloy. This treatment promotes the formation of fine grains on the surface of the alloy, and the grain boundaries act as fast diffusion channels of Cr leading to the Cr effective diffusivity of shot peening samples increase, the Cr effective diffusivity value is 0.235, 4.8 × 10−3, 3.8 × 10−3, 3.7 × 10−3, respectively. It promotes the formation of protective scales for the continuous Cr 2 O 3 layer. Additionally, the effect of grain size on the diffusion of scale-forming elements (Cr, Si and Mn) in the GH3535 alloy was analyzed, with a particular focus on the diffusion of Cr and the synergistic effects of scale-forming element. [Display omitted] • Surface plastic deformation enhances the oxidation resistance of GH3535 alloy. • The grain refinement induced by shot peening promotes Cr outward diffusion. • The oxide scale structure of SP samples contains outer MnCr 2 O 4 and inner Cr 2 O 3. • The formation of SiO 2 about 300 nm under the Cr 2 O 3 layer. [ABSTRACT FROM AUTHOR]