A GND simulation model for micro-deformation mechanism analyses in high-speed cutting Inconel718

The traditional homogeneous JC constitutive model can be used to perform the simulation of the mechanical properties effectively during the cutting process. However, polycrystalline material properties are not considered, and the effect of grain boundaries on the cutting process is ignored. In order to study the effect of grain boundary on micro-deformation during the cutting process of Inconel718, the grain size through the EBSD experiment was obtained firstly. A finite element simulation model of dynamic cutting of 2D polycrystal with grain boundaries was established using Python language and MATLAB software. A new material constitutive model with grain boundary effect is established by introducing the JC model into the geometrically necessary dislocation (GNDs) theory. By writing a VUMAT subroutine to achieve secondary development of ABAQUS, the established constitutive model is used for cutting simulation. Through the comparison of experimental results and simulation results, the model can accurately reflect the changes in cutting force, cutting temperature, and equivalent stress. On this basis, the influence of temperature on geometrically necessary dislocations, the influence of grain boundaries on the evolution of chip morphology, and the initiation and propagation of cracks are further analyzed.