The effect of stresses during crystallization on the crystallite size distributions

In some glasses during thermal annealing, nano crystals are formed, which scarcely grow with time and exhibit a very narrow crystal size distribution. In this paper, considerations on the crystallite size distributions are given. A variant of the nucleation theory including the role of an induction period is included in the model. Since non-isochemical systems are considered, the oversaturation is decreasing with time and therefore a model is chosen according to which the nucleation rate decreases. For the crystal growth velocity, a model recently derived was used which takes into account the stresses formed during the course of the crystallization process. It is found, that a model taking into account decreasing oversaturation, an induction period as well as the occurrence of stresses fully explains the crystallite size distributions experimentally observed which might even be narrower than those according to the theory of Lifshitz, Slyozov and Wagner. (C) 2011 Elsevier Ltd. All rights reserved.