Amorphous to crystalline phase transformations

Abstract

Amorphous or non-crystalline materials can be produced by a variety of techniques including rapid quenching from the melt, vapour deposition, sputtering and ion implantation. The amorphous metallic solids produced by melt quenching, popularly known as metallic glasses, have been found to have a good combination of physical, chemical and mechanical properties and can also be produced in bulk quantities. Metallic glasses are metastable with respect to their crystalline counterparts and thus undergo transformations when subjected to annealing. A knowledge of the 'stability' of the glasses is important before applications fpr these novel materials are thought of. The present paper discusses the thermodynamics, kinetics and mechanisms of crystalization of metallic glasses. Effect of external factors such as high pressure, deformation and irradiation have also been discussed.