Micromechanical study of nano-cutting metal-ceramic WC/Cu by diamond tools

Abstract

In this paper, the effect of the distribution of ceramic particles WC in Cu matrix on the nano-cutting behavior was investigated using molecular dynamics, and the cutting force, friction coefficient, machined surface quality, sub-surface damage depth, atomic displacement and internal defects were systematically studied, and the performance comparison at different cutting speeds was also investigated. It was found that due to the location of the WC phase, the overall removal of the material by the tool can be divided into the following three ways: When WC particles are above the cutting plane, there is less fluctuation in cutting forces and friction coefficients, and less impact on machined surface and subsurface damage; When the WC particles are below the cutting plane, the fluctuation of cutting force and friction coefficient is slow. Meanwhile, shallow craters are produced at the WC location; When the center of mass of WC particles is on the same level as the cutting plane, the cutting force and friction coefficient fluctuate drastically, the quality of the machined surface deteriorates sharply, and at the same time the hard particles pulled out by the tool remain on the machined surface. It was also found that the WC particles underwent different degrees of counterclockwise deflection in the three stages and caused a diversion of the atomic displacement in front of the tool. In addition, different degrees of dislocation plugging are formed between the WC and the tool at different positions, and the density of dislocation lines increases, which makes the substrate near the WC particles strengthened.