It was recalled that the detailed atomic structure of the Σ = 5 (311)[001] tilt grain boundary remained the subject of controversy since structures deduced from high-resolution electron microscopic observations differed from those derived from static calculations. The presence of defects, combined with the effects of temperature, were proposed to be possible causes of this discrepancy. In order to test this hypothesis, defects were incorporated into several configurations of the grain boundary structural unit. Some of these configurations were selected after energy minimization at 0K, and were then studied at high temperatures. The lowest-energy configurations were chosen, in which there were still some remaining defects after relaxation, in order to perform high-temperature simulations using constant-temperature molecular dynamics. A detailed analysis of the results showed that the defects had a tendency to agglomerate. In some cases, this agglomeration could even modify the local periodicity of the grain boundary. By using the average locations of the atoms which resulted from the high-temperature simulations, high-resolution electron microscopic image simulation was performed. Several of the images exhibited features which were also observed in experimental high-resolution electron microscopic images. The degree of agreement between these results and experimental high-resolution electron microscopic images was improved with respect to the structures which resulted from calculations which were performed on configurations without defects.

Molecular Dynamics Simulation of the Atomic Structure of a NiO Tilt Grain Boundary at High Temperature. T.E.Karakasidis, M.Meyer: Modelling and Simulation in Materials Science and Engineering, 2000, 8[2], 117-32