Effect of Workpiece Atom Diffusion Into CBN Tool on Its Mechanical Properties in Cutting Ni–Fe–Cr Alloy Based on Molecular Dynamics Simulation

Abstract

CBN (Cubic Boron Nitride) tool is suitable for precision machining of nickel-based alloy due to its high hardness and chemical inert. Nickel-based alloys are difficult-to-cut material. When high-speed cutting nickel-based alloys with CBN tool, the temperature at tool-workpiece interface is very high. The atoms in workpiece material diffuse into the tool surface and change the performance of cutting tool, resulting in diffusion wear. Inconel 718, which is one kind of widely used nickel-based alloy, is mainly composed of nickel (Ni), iron (Fe) and chromium (Cr). In this paper, the cutting model which describes the single crystal CBN tool cutting Ni–Fe–Cr three-component alloy, and the compression and impact model of CBN tool crystal are established by using molecular dynamics (MD) method to study the diffusion of Ni, Fe and Cr atoms into CBN tool and the effects of diffusion on the properties of CBN crystal tool. The results show that the diffusion of Ni, Fe and Cr atoms into CBN tool decreases the compressive strength and impact toughness of CBN crystals and the effects degree of atom diffusion on the properties of CBN crystals are different.