Heterogeneous nucleation catastrophe on dislocations in superheated crystals

Abstract

Heterogeneous nucleation of melt on dislocations in superheated crystals is analyzed to give a superheating limit for massive heterogeneous nucleation on dislocations, which is evidently lower than the recently developed limit for homogeneous melting. Even for a crystal with a low dislocation density of 102 cm-2 of screw and edge unit dislocations, the associated threshold temperatures are only 1.068 Tm and 1.095 Tm respectively for various metals. It is also notable that the effect of dislocation density on this temperature is limited by the sharp decrease in the critical heterogeneous nucleation energy with increasing temperature.