3-DIMENSIONAL COMPUTER-SIMULATION OF ANISOTROPIC GRAIN-GROWTH IN CERAMICS

Anisotropic abnormal grain growth in ceramics was simulated by a three -dimensional Monte Carlo computer model. Microstructures similar to ex perimental ones were obtained and the influence of energy anisotropy a nd the number of anisotropically growing grains on microstructure deve lopment were studied. It was shown that a single grain with higher int eraction energy in certain directions, embedded in a matrix of normall y growing grains, grows anisotropically in the form of platelets or wh iskers, depending on the spatial energy distribution. Observed growth rates in both promoted and unpromoted directions were constant, but di fferent due to the different growth mechanisms. Faceted grain boundari es were observed. Simulation with low number of anisotropically growin g grains showed bimodal microstructures before grain impingement. Afte r grain impingement thickening of the grains took place until ail the avail able space was consumed. Results of the three-dimensional simula tions agree well with a previous two-dimensional simulation and with e xperimental results. (C) 1998 Acta Metallurgica Inc. Published by Else vier Science Ltd. All rights reserved.