Glass formation and crystallisation in rapidly solidified zirconium alloys

Zirconium-based alloys offer an unique opportunity for studying various aspects of metallic glass, namely glass forming ability, crystallisation modes and kinetics, diffusion mechanisms and formation of glass in bulk. Thermodynamic and kinetic rationale for glass formation have been summarised in binary and ternary metalloid Gee amorphous alloys rich in zirconium. A comparison has been made between the microstructures of the alloys obtained under different cooling rates in order to understand the process of solidification and the process of phase selection. The different types of nucleation processes and the growth mechanisms of crystals in the undercooled melts of Zr-based glass forming alloys have been investigated. Primary, eutectic as well as polymorphic crystallisation have been observed in the alloys of this class of materials. Crystal nucleation and growth kinetics during crystallisation has been examined. (C) 2001 Elsevier Science B.V. All rights reserved.