Nanoscale microstructural factors contributing to the improvement of the micromechanical wear properties of mechanical shot-peened nickel-based superalloys

Mechanical shot peening and other plastic deformation surface-strengthening processes are of great benefit to the improvement of the surface mechanical properties of structural materials in the aviation industry. However, research on the microstructural factors that induce changes in surface mechanical properties remains relatively general. This study provided in-depth insights into the mechanical performance changes induced by mechanical shot peening at the nanoscale of dislocation movement and twinning reactions on the surfaces of materials. Nickel-based superalloy GH4169, a typical application material in the field of aviation manufacturing, was selected as the test material. A mechanical strengthening treatment with 0.25mmA shot peening strength was applied to the GH4169 alloy, and quantitative testing of micromechanical performance indicators, such as microhardness and residual stress was carried out. Based on the observation and analysis of materials with and without surface strengthening using transmission electron microscopy, the correspondence between the micromechanical properties and microstructure changes in the materials was studied. The results showed that under the impact wave of shot peening, the nickel-based superalloy undergoes plastic deformation mainly through dislocations and {111}<112̅> nano twins. The nanoscale microstructure control principle of the surface wear properties of nickel-based superalloys provides theoretical guidance for the formulation of surface-strengthening processes for similar materials.