Investigation on the evolution of surface integrity induced by corundum wheel wear during creep feed grinding of nickel-based superalloy

Abrasive wheel wear inevitably occurs in the process of grinding nickel-based superalloys, which contributes to the deterioration of processing conditions and affects the surface quality. However, the existing research available on the influence mechanism of wheel wear on grinding surface integrity is limited. In this study, the development of thermal-mechanical load in the life cycle of a grinding wheel was explored. The changes in surface integrity resulting from wheel wear were analyzed by investigating surface topography, microstructure and micromechanics, and were verified through fatigue life test. It was observed that slight wear and good self-sharpening significantly decrease the grinding load during the initial and steady wear stages, while maintaining a low surface roughness. The enhanced plastic deformation and low thermal effect lead to the increase of the residual compressive stress and nano-hardness. As abrasive wheel wore following the steady wear stage, the grinding force and temperature increased swiftly and displayed unstable time-domain characteristics. The high thermal-mechanical load induced by attritious wear and material adhesion lead to obvious oxidation and material smearing on the surface. In addition, the subsurface underwent severe plastic deformation and dynamic recrystallization. In terms of mechanical properties, the dominant thermal effect cause residual stress to shift from compressive stress to tensile stress and the degree of work hardening decreased. It was verified that the samples processed by the normally worn wheel exhibited better fatigue performance owing to excellent surface integrity. In contrast, severe wear resulted in a substantial decline in fatigue life.