Numerical simulation of microstructural evolution of ceramic tool materials

摘要

The preparation of ceramic tool materials includes powdering, forming, hot-press fabrication and machining process, and the sintering is a key process, which governs the mechanical properties of the ceramic tool materials as well as the components and content. However, the sintering is a very complicated process. With the rapid development of the computer simulation technology and the computational material science, modeling and numerical simulation of ceramic sintering process become a novel way to investigate the sintering process on the micro- or macro-scale. Monte Carlo Potts' model is widely applied to simulate the solid-phase sintering process of ceramics. Because of no assumption of the particle shape, the model can be properly used to simulate the mass-transport mechanisms. In this paper, a new Monte Carlo Potts' model is proposed to investigate the single- and two-phase material systems, which is based on the Potts' model of the description of the single-phase sintering without the presence of pores. The new simulation algorithm has been utilized to simulate the microstructural evolution in the single- and two-phase ceramic tool material sintering process with considering the presence of pores. Different types of interface, different types of grain boundary energy, initial grain size, the composition content, the initial pore size and the content of pore are considered in the new simulation algorithm. It is found from simulation results that the pore and the phase-two can pin the matrix phase and decrease the growth rate of matrix phase during the microstructural evolution, which has been invalidated by the experiment. The second-phase particle is useful for the refinement of matrix grain. The high rate of grain growth is disadvantage of the pore exhalation. The simulation results are consistent with the experiment results. (C) 2008 Elsevier B.V. All rights reserved.