Glass-forming ability of Ni-Zr-Al alloys: the interplay of thermodynamic and geometric factors

Abstract

ABSTRACT Despite decades of intensive rehearses, we still lack robust and physically clear methods to discover new metallic alloys with high glass-forming ability (GFA). Different empirical criteria proposed to estimate GFA have limited applicability. Here we address the impact of thermodynamic and geometric factors on GFA of Ni-Zr-Al alloys. Using the ideal associated solution model, we calculated the Gibbs energy and the mixing enthalpy of the system and compared the results with available experimental and theoretical data. The results show that the model used is a good approximation for calculating the thermodynamic properties of liquid alloys if both binary and ternary compounds are explicitly taken into account. However, we conclude that it is hardly possible to address GFA of Ni-Zr-Al alloys using only thermodynamic properties. We test a few different criteria, proposed in the literature, and show that they also fail to explain GFA in the system. Then, we propose new parameters based on Gibbs mixing energy and effective difference in atomic radii, which allows localising the composition domain corresponding to the best GFA in Ni-Zr-Al alloys. Our findings open up the prospects to develop reliable theoretical methods for discovering new metallic glasses.