Role of the interface in ion-induced alloy phase formation in an immiscible Y-Ta system

Publisher Website
Google Scholar
Abstract
In an immiscible Y-Ta system with a heat of mixing exceeding +27 kJ/mol, amorphous alloys were obtained by room temperature 200-keV xenon-ion mixing of the Y-Ta multilayered films. In addition, three new metastable crystalline phases, i.e., an fcc phase in Y-rich films, as well as an hcp and another fcc phase in Ta-rich films, were observed after ion mixing. To give a thermodynamic interpretation of these anomalous alloying behaviors, a Gibbs-free-energy diagram of the system was constructed based on the Miedema model of heat of formation and a calculation method suggested by Alonso; this method allowed the free-energy curves of the solid solutions, the amorphous phase, the three metastable crystalline phases, and especially that of the Y-Ta multilayered films containing excess interfacial free energy, to be calculated and included. It was found that the excess interfacial free energy stored in the multilayered films could raise the initial energetic state of the multilayers and therefore played an important role in ion-mixing-induced alloy phase formation in this immiscible system.

This publication has 1 reference indexed in Scilit: