ELASTIC STRESS EFFECTS ON CRITICAL CLUSTER SHAPES

Crystallization of solids at planar solid-air surfaces was analyzed. S hape and size of clusters of the newly evolving phase are determined w hich correspond to the minimal work of cluster formation in nucleation . Both elastic field and surface energy terms are taken into considera tion. This work is not restricted to the consideration of spherical in terfaces cluster-ambient solid phase but allows, more general arbitrar y shapes of the new phase. Application to crystallization of glassform ing melts, gives additional support to the idea that differences in th e degree of evolution of elastic strains in crystallization in the bul k and near external or internal surfaces of highly viscous glassformin g melts in the vicinity of the temperature of vitrification T-g may be the origin for the preferential surface crystallization of glasses. ( C) 1998 Elsevier Science B.V. All rights reserved.