Surface residual stress in high speed cutting of superalloy Inconel718 based on multiscale simulation

Inconel718 is one kind of nickel-based superalloy strengthened by body centered tetragonal γ ″ and face centered cubic γ ′ precipitation, which has a high yield strength, high corrosion resistance and oxidation resistance at high temperature. Alloying elements exist in the form of high hardness compounds, such as TiC, NbC and other interphase hard point. These high hardness compounds result in the presence of high cutting temperature, large plastic deformation, especially the generation of residual stress in the machined surface. In this paper, the multi-scale finite element model of Inconel718 is established, and the cohesive element is added into the brittle phase particles to conduct the cutting simulation process. The accuracy of the established model is verified according to the chip morphology and the cutting force. The formation mechanism and distribution law of residual stress in the machined surface is studied deeply. The results show that the simulation results of the multi-scale finite element model which adds the brittle phase particles are closer to the experimental results. The larger the size of the brittle phase particles is, the smaller the residual stress of the workpiece is. Along the depth direction of workpiece, the influence of the brittle phase particles on the residual stress is getting smaller and smaller. This study provides a theoretical basis and reference for the further optimization of Inconel718 cutting performance and surface integrity.