深过冷液态金属Cu的热物理性质和原子分布

发布时间：2018-01-13 03:33

本文关键词：深过冷液态金属Cu的热物理性质和原子分布　出处：《金属学报》2017年08期 　论文类型：期刊论文

【摘要】：针对液态金属Cu在深过冷亚稳条件下的热物理性质和液态结构数据缺乏的问题,采用分子动力学方法结合修正嵌入原子势,研究了常规液态和亚稳液态金属Cu的热物理性质(熔点、密度、比热容和自扩散系数)和原子分布规律,体系温度范围为800~2400 K,最大过冷度达到556 K。通过构建晶体-液体-晶体结构,探索了金属Cu的熔化过程,获得最优的熔点计算温度为1341 K,与实验值误差1.11%。获得了宽广温度范围内液态金属Cu的密度随温度的变化规律,采用Mishin势函数计算的熔点处密度模拟值为7.86 g/cm~3,与文献报道的实验结果的误差小于2%。液态金属Cu的焓在800~2400 K范围内随温度呈线性关系变化,即比热容几乎不随过冷度变化而变化,而自扩散系数则随温度呈指数关系变化。根据不同温度原子的位置变化,获得了相应的双体分布函数,发现液态体系始终处于短程有序、长程无序的状态,且原子短程有序度随温度升高而降低,短程有序结构仅保持在3~4个原子间距范围内,且随间距增大而展现出典型的无序特征。
[Abstract]:In order to solve the problem of the lack of thermo-physical properties and liquid structure data of liquid metal Cu under the condition of deep supercooling metastable, the molecular dynamics method combined with modified embedded atom potential was adopted. The thermo-physical properties (melting point, density, specific heat capacity and self-diffusion coefficient) and atomic distribution of Cu, a conventional liquid and metastable liquid metal, have been studied. The temperature range of the system is 800 ~ 2400K. The maximum undercooling is up to 556K. The melting process of Cu is investigated by constructing the crystal liquid-crystal structure. The optimum melting temperature is 1341K. The density of liquid metal Cu varies with temperature in a wide range of temperatures. The simulated melting point density calculated by Mishin potential function is 7.86 g / cm ~ (-3). The experimental results are less than 2. The enthalpy of liquid metal Cu varies linearly with temperature in the range of 800 ~ 2400K, that is, the specific heat capacity almost does not change with the undercooling degree. The self-diffusion coefficient varies exponentially with temperature. According to the positions of atoms at different temperatures, the corresponding catamorphic distribution function is obtained. It is found that the liquid system is always in the state of short range order and long range disorder. The short range order degree of atoms decreases with the increase of temperature, and the short range order structure is only kept in the range of 3 ~ 4 atoms, and it shows a typical disorder characteristic with the increase of the distance between atoms.
【作者单位】：西北工业大学应用物理系;
【基金】：国家自然科学基金项目Nos.51474175和51522102 陕西省工业科技攻关项目No.2015GY138~~
【分类号】：O562
【正文快照】： 液态金属尤其是亚稳液态金属的热物理性质和原子分布规律是凝聚态物理、材料物理和流体物理领域的重要研究课题,与之相关的重要热物理性质主要包括密度、比热容、扩散系数、黏度和表面张力等。其中,密度是金属最基本的性质,而熔点附近密度变化规律对理解凝固过程十分关键;比热

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