Model Establishment of a Co-Based Metal Matrix with Additives of WC and Ni by Discrete Element Method

A metal matrix is an indispensable component of metal-bonded diamond tools. The composition design of a metal matrix involves a number of experiments, making costly in terms of time, labor, and expense. The discrete element method (DEM) is a potential way to relieve these costs. The aim of this work is to demonstrate a methodology for establishing and calibrating metal matrix's DEM model. A Co-based metal matrix with WC and Ni additives (CoX⁻WC⁻Ni) was used, in which the Co-based metal was Co⁻Cu⁻Sn metal (CoX). The skeletal substances in the metal matrix were treated as particles in the model, and the bonding substances were represented by the parallel bond between particles. To describe the elasticity of the metal matrix, a contact bond was also loaded between particles. A step-by-step calibration procedure with experimental tests of three-point bending and compression was proposed to calibrate all microcosmic parameters involved during the establishment of DEM models: first for the CoX matrix, then for the CoX⁻WC matrix and CoX⁻Ni matrix, and finally for the CoX⁻WC⁻Ni matrix. The CoX⁻WC⁻Ni DEM model was validated by the transverse rupture strength (TRS) of two new compositions and the results indicated that the model exhibited a satisfactory prediction ability with an error rate of less than 10%.