Thermodynamics and Glass Forming Ability from the Liquid State

Abstract

AbstractThis study is mainly devoted to the establisment of relations between easy glass forming ability of some multicomponent liquid alloys and strong heteroatomic bonding in connection with nucleation. The chemical short range order in typical liquid bulk glass formers as Zr-Ni-AI is evaluated from a statistical model and presented as Cowley's order parameters versus concentration. The effect of the nature and of the number of components on the chemical contribution to the liquid-crystal interface energy and on the Gibbs energy of crystallisation is analysed and discussed. A specific mechanism of nucleation based on a distribution of concentration fluctuations in the undercooled liquid is proposed. This homophase fluctuation mechanism, which is thermodynamically and kinetically justified, leads to a lower preexponential factor in the expression of the frequency of nucleation as a function of the number of components. Furthermore, this frequency of nucleation can be strongly lowered by an augmentation of the energy barrier of nucleation depending on the nature and the number of components in the liquid phase.