結晶粒組織形態におよぼす結晶粒成長異方性の影響

抄録

Morphological changes in two-dimensional grain structures have been studied by computer simulation on the basis of assumption of random nucleation sites and randomly oriented ellipsoidal growth. Wide ranges of grain growth anisotropy are given by limiting the growth rate of minor axis on the ellipsoidal growth. Coefficients of variation of the distributions of grain area, grain size and sides per grain increase with increasing growth anisotropy and growth rate. Morphological characteristic values of 4πA⁄P², LD⁄BR and CP⁄P are calculated for each case, where A, P, LD, BR and CP represent the grain area, perimeter, longest dimension, breadth and convex perimeter, respectively. With increasing growth anisotropy, the values of 4πA⁄P² and CP⁄P decrease and the value of LD⁄BR increases. The formation process of the dendrite structure of Al-4.3 mass%Cu is estimated by comparison with the result of computer similation study that the growth rate along the major axis is 0.25 at the growth anisotropy of 2.0.