Monte-Carlo simulation of the microstructure evolution in HCP materials

초록

In order to investigate the effect of GBCD (Grain Boundary Character Distribution) on the evolution of microstructure in HCP materials, a Monte-Carlo simulation method was developed in which the texture of real material was closely reconstructed in the simulated microstructure. The method consists of extracting the volume fraction and the Gaussian half-width from the experimental ODF and installing them into the simulated microstructure. For the range of c/a=1.55~1.633, GBCD of reference material with non-random orientation was calculated from randomly oriented microstructure up to 19. The distribution of misorientation angles and CSL boundaries agreed well with theoretical predictions. GBCD was also calculated from an ODF map of pure Ti in the literature. In this study, the frequency of 1 boundaries was found to increase with the intensity of the preferred orientation. The distribution frequencies of CSL and 1 boundaries were high when two texture components had a CSL relationship. From the study of varied spatial distribution of grains, it was also found that the distribution frequency of 1 boundaries was high in the microstructure containing coarse grains of main texture components due to clustering. The result favorably agreed with the previously reported cases of real materials using different analytical techniques. The computer-generated initial microstructure, therefore, demonstrated a sound base for the study of microstructure evolution in HCP materials.