4H-SiC specimens were plastically deformed by basal slip at between 800 and 1300C. Samples were investigated by means of transmission electron microscopy and high-resolution techniques. The accepted transition temperature (1030C) was found not to be actually so well defined since the two mechanisms were operating together between 1000 and 1100C. Dissociation of basal dislocations takes place over the entire temperature range investigated, having a different influence on each regime. In the high temperature regime, after dissociation the two partials slip together in the basal plane fringing a stacking fault. The dissociation width was determined, yielding a stacking fault energy of 20mJ/m2. However, below the transition temperature the difference in mobility of the partials and the low stacking fault energy allowed the leading partial to glide alone. the consequences of this finding for the crystal structure (cubic bands nucleation) and mechanical behaviour (high work-hardening rate) were considered.

Dislocation Microstructure of 4H-SiC Single Crystals Plastically Deformed Around the Transition Temperature. A.Lara, M.Castillo-Rodríguez, A.Muñoz, A.Domínguez-Rodríguez: Journal of the European Ceramic Society, 2012, 32[2], 495-502