Nucleation in silicate and metallic glasses

摘要

The formation and stability of silicate andmetallic glasses are discussed. Selected examples ofthe time-dependent nucleation rates of crystal andquasicrystal phases in polymorphic and non-polymorphic transformations of liquids and glassesare presented. The kinetic model for the classicaltheory of nucleation is adequate to understand thenucleation of a phase with the same composition as theparent phase. Recent studies of nucleation in silicateglasses as a function of composition, anddevitrification studies in bulk metallic and Al-rareearth metallic glasses, however, suggest that it maynot he adequate when chemical partitioning occursduring nucleation. This is particularly relevant forunderstanding the micro-structural developmentduring the devitrification of bulk metallic glasses.Other proposed approaches are examined.