COMPUTER-SIMULATION OF ANISOTROPIC GRAIN-GROWTH IN CERAMICS

Anisotropic grain growth in ceramics has been simulated by a Monte Car lo computer model. Microstructures, similar to experimental ones, were obtained and the influence of the energy anisotropy and the number of anisotropical grains on microstructure development were studied. It w as shown that a single grain with higher energy in one direction, embe dded in a matrix of grains with the isotropic boundary energy, grows a nisotropically with a nearly constant rate. The growth rate is linearl y proportional to the energy anisotropy of the grain. The aspect ratio increases with the cube root of time. Faceted grain boundaries were s imulated. Microstructures with less than 50% of anisotropic grains dev elop, after a short time, a bimodal grain size distribution. At this p oint, the mean aspect ratio of anisotropic grains reaches a maximum. T he heights of the maxima are proportional to the energy anisotropy and inversely proportional to the fraction of anisotropic grains. Weighte d aspect ratio distributions and their mean values agree well with exp erimental data.