The crossing ranges of twin layers which formed in monocrystals under uniaxial loading at constant deformation rates of between 5 and 30μ/min, and temperatures ranging from 450 to 850C, were investigated by using optical methods. Crystallographic analysis of the possible twin crossings was carried out in a pseudo-cubic system in order to investigate the compatibility of these crossings. It was shown that, among the 4 possible types of crossing of the various types of layer, only one type could lead to a coherent crossing. In the latter case, according to the pseudo-cubic model which was considered, all 4 orientation states occurred in the structural domains that were separated by this type of crossing. The other 3 types of crossing were not coherent, and resulted in crack formation.

A.H.Kalantarian, G.L.Mayilyan, A.D.Gladun, R.A.Vardanian: Philosophical Magazine A, 1997, 76[2], 319-28