Elastic Properties and Glass Forming Ability of the Zr_(50)Cu_(40)Ag_(10) Metallic Alloy

摘要

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 a, 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. Nonmonotonic 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≈64 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.