Computer simulation of the anisotropic crystal growth in WC

초록

The process of triangular prism formation and abnormal grain growth of WC was modeled using pseudo Monte-Carlo simulation based on atomic absorption and coalescence mechanism. It was hypothesized that grains of WC evolve into a triangular prism-shape due to {10-10} and {1-210} planes of fast growth rate. Furthermore, coalescence of {10-10} and {1-100} planes subsequent to the anisotropic evolution was considered to be the main reason for the abnormal grain growth. Therefore the anisotropy in growth rate, which was caused by difference in packing characteristics of W and C atoms on each crystal plane, was responsible for the nucleation of prism shape grains. Computer simulation of the anisotropic growth was conducted by constructing a system consisting of 30x30 lattice points, in which W and C atoms were allowed to form crystal nuclei according to the Jackson’s law of anisotropic atomic adsorption. Coarsening of crystals was modeled as a process of coalescence of the nuclei. The probability of coalescence computed by the Monte-Carlo method agreed well with a theoretical prediction.