Correlated thermodynamic, structural, and mechanical properties of CuZrAl metallic glasses with varying Al concentrations

Abstract

Atomic composition is a key factor governing the structure-property relationships in metallic glasses (MGs). In this work, the effect of Al concentration on the thermodynamic, structural, and mechanical properties of Cu 50Zr 50−xAl x MGs ( x=0, 1, 3, 5, 7, 9, and 11 at.%) was investigated using molecular dynamics simulations. Five independent configurations were considered for each composition to improve statistical reliability. Increasing Al concentration increased the glass transition temperature and thermal expansion coefficient while reducing the atomic volume. Structural analysis revealed that Al addition modifies the chemical short-range order, promotes the formation of solid-like polyhedra, and increases the population of 3-atom connections between them. In addition to these structural changes, elastic properties such as Young’s modulus, bulk modulus, and shear modulus also increased with Al concentration, as well as plastic properties such as maximum stress, flow stress, and stress drop, with an increase of up to 27% in the maximum stress, indicating an overall strengthening of the MGs. Spearman’s correlation coefficient and principal component analysis (PCA) were also employed to provide a quantitative measure of the correlation between the calculated properties and Al concentration. In the PCA, the first component accounted for 95.9% of the total variance, while the second component accounted for 1.8%. Overall, these results demonstrate that Al concentration modifies the structure of CuZrAl MGs, producing correlated changes in their thermodynamic and mechanical responses.