Elastic Properties and Glass Forming Ability of the Zr$_{50}$Cu$_{40}$Ag$_{10}$ Metallic Alloy

TL;DR

This study uses molecular dynamics simulations to analyze the elastic properties and glass forming ability of Zr50Cu40Ag10 alloy, revealing significant changes during the liquid-glass transition and confirming its good glass forming potential.

Contribution

It provides detailed molecular dynamics insights into the elastic behavior and fragility index of Zr50Cu40Ag10 alloy, linking microscopic properties with glass forming ability.

Findings

Shear and Young's moduli increase by over 50% at the glass transition.

Poisson's ratio drops sharply to near zero, indicating brittleness.

Fragility index m ≈ 64 aligns with experimental data.

Abstract

The elastic properties of the Zr$_{50}$Cu$_{40}$Ag$_{10}$ metallic alloy, such as the bulk modulus $B$, the shear modulus $G$, the Young's modulus $E$ and the Poisson's ratio $\sigma$, are investigated by molecular dynamics simulation in the temperature range $T=250-2000$ K and at an external pressure of $p = 1.0$ bar. It is shown that the liquid-glass transition is accompanied by a considerable increase in the shear modulus $G$ and the Young's modulus $E$ (by more than $50\%$). The temperature dependence of the Poisson's ratio exhibits a sharp fall from typical values for metals of approximately $0.32-0.33$ to low values (close to zero), which are characteristic for brittle bulk metallic glasses. Non-monotonic temperature dependence of the longitudinal and transverse sound velocity near the liquid-glass transition is also observed. The glass forming ability of the alloy is evaluated in terms of the fragility index $m$. As found, its value is $m\approx64$ for the Zr$_{50}$Cu$_{40}$Ag$_{10}$ metallic glass, that is in a good agreement with the experimental data for the Zr-Cu-based metallic glasses.