Phase evolution and strengthening mechanism induced by grinding hardening

In the abrasive grinding hardening (AGH) of metal materials, the microstructure of the surface changes under the action of the intense grinding heat and forms the evolution layer covering the grinding surface with unique mechanical properties. The effective control of microstructure in the layer has great practical significance for obtaining high-performance surfaces. However, the formation mechanism of evolution layer is not well revealed and few quantitative investigations on microstructure phase content and morphology, which hinders the development of advanced grinding technology and surface performance characterization methods. A novel digital twin model is proposed; the spatial–temporal distribution of grinding heat and the evolution of microstructure along the surface depth direction have been reproduced from the microscale. The results reveal the dynamic effect of grinding parameters on phase content and morphology of the evolution layer. Furthermore, the quantitative relationship between microstructure and surface macroscopic hardening characteristics has been explored, and a novel method is proposed to predict the surface hardness. This research enhances the understanding of the formation mechanisms of grinding hardened surface and is significant to realize effective control and accurate prediction of surface performance.