Free Energy Criteria for Glass Forming Alloys

Abstract

The thermodynamic characterisation of a number of glass forming systems (Au – Si, Pd – Si, Ni – Ti, Ti – Be, Zr – Be and Hf – Be) has been reviewed, and the free energy curves calculated for the glass forming temperature as well as for the temperature of maximum rate of crystallisation, in order to check how far the data which models the equilibrium diagrams provides suitable guidance for metallic glass formation. It is shown that the glass forming range is accurately predicted from the region where the liquid phase is more stable than other competing single phases, thus confirming the importance of the T₀ concept. The systems considered offer a variety of behaviour which emphasises the importance of metastable compound formation as well as the inhibition of some equilibrium compounds. The present treatment is compared with other approaches to the problem.