A modified constitutive model considering dynamic recrystallization behavior for cutting Inconel 718

Abstract

The microstructure evolution significantly affects the cutting process by modifying the workpiece material mechanical behavior. Dynamic recrystallization (DRX) in the cutting process of Inconel 718 induces significant microstructure evolution below the machined surface, leading to changes in output responses including cutting force, temperature distribution, residual stress and so on. In this work, a material constitutive model including the effect of DRX behavior on the flow stress for cutting Inconel 718 alloy is developed. The volume fraction of DRX is introduced as an internal state variable of Johnson-Cook (JC) constitutive model. The DRX kinetics model parameter is determined by using Oxley's parallel-sided shear zone theory for the orthogonal cutting. Orthogonal cutting experiments with high cutting speed and a series of finite element (FE) simulations by the modified model, JC model and TANT model are carried out. And the effectiveness of the modified model is verified by the comparison of the experimental and simulated data. The results show that the proposed material model not only has higher prediction accuracy on the cutting force compared with JC model and TANT model, but also can accurately predict the chip morphology. And the microstructure distribution in chip simulated by the modified material model is consistent with the experimental results. This model will be attractive to the FE simulation of the microstructure evolution for cutting Inconel 718 alloy.