Local atomic structure in equilibrium and supercooled liquid Zr(75.5)Pd(24.5).
Local atomic structure in equilibrium and supercooled liquid Zr(75.5)Pd(24.5).
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DOI：
10.1063/1.4737381
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发表时间：
2012-07
期刊：
影响因子：
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通讯作者：
N. Mauro;W. Fu;J. Bendert;Y. Cheng;E. Ma;K. Kelton
中科院分区：
文献类型：
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作者：
N. Mauro;W. Fu;J. Bendert;Y. Cheng;E. Ma;K. Kelton
采用束线静电悬浮（BESL）技术，在高真空、无容器的环境中，通过原位高能同步辐射衍射测量，获得了平衡态和过冷态共晶Zr（75.5）Pd（24.5）液体的原子结构。反向Monte Carlo拟合的X-射线静态结构因子，约束使用从从头算分子动力学模拟获得的部分对相关函数，表明存在的中程顺序（MRO）的形式的一个强烈的倾向Pd-Pd（溶质-溶质）避免。这种有序性在研究的整个温度范围内持续存在，从平衡液相线温度以上170 °C到低于平衡液相线温度263 °C。此外，对获得的原子结构的定量分析表明，钯原子周围存在适度的二十面体状局部有序性，随着温度的降低，团簇显示出越来越多的共面倾向，以形成更扩展的结构。
Atomic structures were obtained in equilibrium and supercooled eutectic Zr(75.5)Pd(24.5) liquids by in situ high-energy synchrotron diffraction measurements using the beamline electrostatic levitation (BESL) technique, which provides a high-vacuum, containerless, environment. Reverse Monte Carlo fits to the x-ray static structure factors, constrained using partial pair correlation functions obtained from ab initio molecular dynamics simulations, indicate the presence of medium-range order (MRO) in the form of a strong tendency for Pd-Pd (solute-solute) avoidance. This order persists over the entire temperature range studied, from 170 °C above the equilibrium liquidus temperature to 263 °C below it. Further, a quantitative analysis of the atomic structures obtained indicates a modest degree of icosahedral-like local order around Pd atoms, with the clusters showing an increased tendency for face-sharing to form more extended structures with decreasing temperature.