Department of Applied Physics, Chang'an University, Xi'an, 710064, China.
J Phys Chem B. 2012 Jul 5;116(26):7746-53. doi: 10.1021/jp301576f. Epub 2012 Jun 21.
The atomic mechanism of liquid-glass transition for Ca(7)Mg(3) alloy during the rapid quenching processes is studied by the molecular dynamics simulations. The temperature dependences of structural, thermodynamic, and dynamic properties during the liquid-glass transition have been investigated. It is found that onset temperatures where these different properties begin to deviate from the equilibrium liquid are identical and near the melting temperature T(m). The liquid-glass transition temperatures in structure (T(g)(Str)) and dynamics (T(g)(Dyn)) are identical and higher than the calorimetric one (T(g)(Cal)), which are consistent with many experiments and computer simulations. The solid- and liquid-like atoms are defined by the Debye-Waller factor. It reveals that the solid-like atoms hold lower potential and higher degree of local order. On the basis of the evolution of solid-like atoms, the atomic mechanisms in structure, thermodynamics, and dynamics transition are systematically elucidated, which are consistent with the potential energy landscape.
通过分子动力学模拟研究了快淬过程中 Ca(7)Mg(3) 合金的液体-玻璃转变的原子机制。研究了液体-玻璃转变过程中结构、热力学和动力学性质的温度依赖性。结果发现，这些不同性质开始偏离平衡液体的起始温度相同，且接近熔点 T(m)。结构中的液体-玻璃转变温度 (T(g)(Str)) 和动力学中的液体-玻璃转变温度 (T(g)(Dyn)) 相同且高于量热法测定的液体-玻璃转变温度 (T(g)(Cal))，这与许多实验和计算机模拟结果一致。通过德拜-沃勒因子定义了固态和液态原子。结果表明，固态原子具有较低的势能和较高的局部有序度。基于固态原子的演化，系统地阐明了结构、热力学和动力学转变的原子机制，这与势能景观一致。
