First-principles sliding simulation of Al-terminated Σ13 pyramidal twin grain boundary in α-Al2O3

Abstract

First principles plane wave basis calculations were performed to investigate the atomic-scale mechanism of grain boundary (GB) sliding of the Al-terminated Σ13 pyramidal twin GB in α-Al2O3 in order to investigate the difference in sliding properties from the previously reported result of O-terminated GB. Atomistic mechanism of sliding process was found to be similar to the previously reported O-terminated GB, that is, the sliding takes place with successive breaking/rebonding of Al–O bonds across the GB core [Nakamura et al., Phys. Rev. B 75 (2007) p.184109]. On the other hand, it was found that sliding resistance of the Al-terminated GB is higher than that of the O-terminated one, though they have the identical orientation relationship. Quantitative chemical bonding analyses show that the difference in the sliding resistance originates from the local Al–O bonding characteristics of individual Al–O pairs across the GB plane.