Glass formation and crystallisation in rapidly solidified zirconium alloys

Zirconium-based alloys offer an unique opportunity for studying various asp ects of metallic glass, namely glass forming ability, crystallisation modes and kinetics, diffusion mechanisms and formation of glass in bulk. Thermod ynamic and kinetic rationale for glass formation have been summarised in bi nary and ternary metalloid Gee amorphous alloys rich in zirconium. A compar ison has been made between the microstructures of the alloys obtained under different cooling rates in order to understand the process of solidificati on and the process of phase selection. The different types of nucleation pr ocesses and the growth mechanisms of crystals in the undercooled melts of Z r-based glass forming alloys have been investigated. Primary, eutectic as w ell as polymorphic crystallisation have been observed in the alloys of this class of materials. Crystal nucleation and growth kinetics during crystall isation has been examined. (C) 2001 Elsevier Science B.V. All rights reserv ed.