Pressure Effects on the Transport and Structural Properties of Metallic Glass-Forming Liquid

• 作者: Duo-Hui Huang Fan-Hou Wang Jun-Sheng Yang Qi-Long Cao
• 来源期刊: 中国物理快报（英文版）
• 年，卷（期）: 2020,（7）
• 所属期刊栏目: CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES
• 页码范围: 56-60
• 页数: 5页
• 语种: 英文
• DOI: 10.1088/0256-307X/37/7/076201

摘要

Transport and structural properties of metallic glass-forming liquid Cu50Zr50 are investigated by molecular dynamics simulation,under high pressures from 1 bar to 70 GPa.The following results have been obtained: (i) reversals of component diffusion coefficients (DCu and DZr) are observed at the reversion pressure.At low pressures below the reversion pressure,DCu/DZr decreases from about 1.4 to 1.0.At high pressures above the reversion pressure,DCu/DZr decreases more rapidly from 1.0 to about 0.7.(ii) Component diffusion coefficients decay exponentially with pressure up to reversion pressure,then the strength of the exponential dependence changes,while the pressure-dependent behavior of viscosity can be well described by a single exponential relation over the full range of pressure.(iii) The Stokes-Einstein relation (SER) works well at low pressures and starts to be violated at the breakdown pressure.For glass-forming liquid Cu50Zr50 along the 2000 K isotherm,the breakdown pressure equals the reversion pressure of component diffusion coefficients and is about 35 GPa.(iv) The pressure dependences of the ratio between component diffusion coefficients can be used to predict the breakdown pressure of SER along isotherm.The validity of SER and the reversals of component diffusion coefficients are found to be related to the pressure dependence of the relative total fractions of predominant Voronoi polyhedrons around individual components.