本文關(guān)鍵詞：深過冷液態(tài)金屬Cu的熱物理性質(zhì)和原子分布　出處：《金屬學(xué)報(bào)》2017年08期 　論文類型：期刊論文

  更多相關(guān)文章： 深過冷 液態(tài)金屬 熱物理性質(zhì) 雙體分布函數(shù)

【摘要】：針對(duì)液態(tài)金屬Cu在深過冷亞穩(wěn)條件下的熱物理性質(zhì)和液態(tài)結(jié)構(gòu)數(shù)據(jù)缺乏的問題,采用分子動(dòng)力學(xué)方法結(jié)合修正嵌入原子勢(shì),研究了常規(guī)液態(tài)和亞穩(wěn)液態(tài)金屬Cu的熱物理性質(zhì)(熔點(diǎn)、密度、比熱容和自擴(kuò)散系數(shù))和原子分布規(guī)律,體系溫度范圍為800~2400 K,最大過冷度達(dá)到556 K。通過構(gòu)建晶體-液體-晶體結(jié)構(gòu),探索了金屬Cu的熔化過程,獲得最優(yōu)的熔點(diǎn)計(jì)算溫度為1341 K,與實(shí)驗(yàn)值誤差1.11%。獲得了寬廣溫度范圍內(nèi)液態(tài)金屬Cu的密度隨溫度的變化規(guī)律,采用Mishin勢(shì)函數(shù)計(jì)算的熔點(diǎn)處密度模擬值為7.86 g/cm~3,與文獻(xiàn)報(bào)道的實(shí)驗(yàn)結(jié)果的誤差小于2%。液態(tài)金屬Cu的焓在800~2400 K范圍內(nèi)隨溫度呈線性關(guān)系變化,即比熱容幾乎不隨過冷度變化而變化,而自擴(kuò)散系數(shù)則隨溫度呈指數(shù)關(guān)系變化。根據(jù)不同溫度原子的位置變化,獲得了相應(yīng)的雙體分布函數(shù),發(fā)現(xiàn)液態(tài)體系始終處于短程有序、長程無序的狀態(tài),且原子短程有序度隨溫度升高而降低,短程有序結(jié)構(gòu)僅保持在3~4個(gè)原子間距范圍內(nèi),且隨間距增大而展現(xiàn)出典型的無序特征。
[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.
【作者單位】： 西北工業(yè)大學(xué)應(yīng)用物理系;
【基金】：國家自然科學(xué)基金項(xiàng)目Nos.51474175和51522102 陜西省工業(yè)科技攻關(guān)項(xiàng)目No.2015GY138~~
【分類號(hào)】：O562
【正文快照】： 液態(tài)金屬尤其是亞穩(wěn)液態(tài)金屬的熱物理性質(zhì)和原子分布規(guī)律是凝聚態(tài)物理、材料物理和流體物理領(lǐng)域的重要研究課題,與之相關(guān)的重要熱物理性質(zhì)主要包括密度、比熱容、擴(kuò)散系數(shù)、黏度和表面張力等。其中,密度是金屬最基本的性質(zhì),而熔點(diǎn)附近密度變化規(guī)律對(duì)理解凝固過程十分關(guān)鍵;比熱

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