The (111)Nb||(00▪1)sapphire interface was modelled atomistically by using a simple description of the atomic interactions. The object was to determine the effect of the strength of bonding between the 2 materials upon the misfit dislocations which formed in Nb at, or near to, the interface. The calculations showed that 2 types of networks of misfit dislocations could form, depending upon the strength of bonding. Only a triangular network, with ½<111> dislocations, occurred if transport of material by diffusion, etc, could take place. This was the network type which was revealed by electron microscopy. The core structure of the misfit dislocations also depended upon the strength of bonding. A comparison of simulated high-resolution electron microscopic images with observations indicated that there was excellent agreement, for a reasonable strength of bonding.

Atomic Level Studies of Dislocation Networks in Niobium/Sapphire Interfaces. A.Lévay, G.Möbus, V.Vitek, M.Rühle, G.Tichy: Materials Science Forum, 1999, 294-296, 199-202