| Cu3Au合金熔体的中程有序结构 |
| Medium-range Order Structure in Liquid Cu3Au Alloy |
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| 摘要: 采用紧束缚(Tight-binding,简称TB)原子间相互作用势,利用分子动力学模拟(Molecular Dynamics,简称MD)的方法研究了Cu3Au合金熔体的微观结构,发现Cu3Au合金体系在高于熔点以上的400K～500K的温度范围内,结构因子上存在预峰,且在此范围内,随着温度的升高,预峰的强度逐渐降低。当温度超过1764K时,预峰开始消失。通过Lorentzian近似和Scherrer公式,可得预峰所对应的原子团簇尺寸位于1.35nm～1.85nm之间,属于中程有序结构范畴。Bhatia-Thornton(BT)偏结构因子表明,预峰的起源应归咎于体系中存在的化学序与拓扑序。BT形式的双体分布函数也证实,体系中存在着较强的化学序,且团簇中原子间的配位倾向于同类原子的配位。 |
| 关键词: Cu3Au合金熔体 结构因子 预峰 中程有序 |
| 基金项目: |
| Abstract: The microstructure of liquid Cu3Au alloy is studied by molecular dynamics simulation, based on Tight-binding (TB) potential. It is found that there exist prepeaks in the structural factors among 400～500K above melting point. With temperature increasing, the intensity of prepeak gradually decreases. When temperature exceeds 1764K, the prepeak in the structural factor disappears. Lorentzian approximation and Scherrer formula indicate that sizes of atomic clusters lie between 1.35nm～1.85nm, which belongs to the range of MRO. It is shown from Bhatia-Thornton (BT) partial structural factor that the origin of prepeak should be attributed to the chemical-range ordering(CRO) and topological-range ordering(TRO) in the system. The pair distribution function with BT modality also approves that there exists strong chemical ordering in the liquid Cu3Au alloy, and indicates the preference for like-neighbor bonds in the liquid. |
| Keywords: liquid Cu3Au alloy structure factor prepeak medium-range order |
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| 摘要点击次数: 1074 |
| 全文下载次数: 1897 |
| 丛红日,边秀房,李辉.Cu3Au合金熔体的中程有序结构[J].无机化学学报,2002,18(5):455-459. |
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