The first ab initio calculations were made, of the tensile strength and fracture of a coincidence boundary, by using a molecular dynamics method which was based upon density functional theory. The non-polar interface of the {122} Σ = 9 boundary was considered. The stable configuration contained reconstructed 5-membered and 7-membered rings plus interfacial C-C and Si-Si wrong-bonds. The interface was very strong because of reconstruction, although the C-C and Si-Si bonds had a large effect. The back-bond of the C-C bond was broken first because of the short bond-length and high strength of the C-C bond. The interfacial Si-C bonds were then broken, and the Si-Si bond.

Ab initio Tensile Tests of Grain Boundaries in SiC. M.Kohyama: Materials Science Forum, 1999, 294-296, 657-60