钴和铁熔体短程序的分子动力学模拟

通过分子动力学模拟研究了金属钴和铁熔体从普通液态到过冷液态普通微观结构的性质.所计算两体分布函数与可获得的实验结果基本一致,从普通液态到过冷液态的局域结构中的原子配位数为11和12的分布几率随着温度的降低而变小,而原子的配位数大于12的分布几率反而增加,角分布函数位于55.有一个明显的峰,位于110°有一个宽展的峰,位于150°有一个肩膀,表明金属钴和铁熔体的微观局域结构要比规则的二十面体团簇的结构复杂得多.我们的模拟结果表明金属熔体中的二十面体短程序随着温度的降低而增加,并在过冷液态中而占优势.

Investigation of short-range order in metallic melts Co and Fe by ab initio molecular dynamics

We have performed ab initio molecular dynamics simulations of metallic melts Co and Fe in stable and undercooled melts.The structural properties and their temperature dependence were studied.The calculated pair correlation functions are in agreement with available experimental data.Going from the stable liquid to the undercooled state.the fraction of coordination numbers 11 and 12 becomes lass but the fraction of coordination numbers more than 12 becomes more.The calculated bond-angle distributions show a prominent peak θ～55°,a broad peak θ～110°and a small shoulder θ～150°,indicating that the local structure of Co and Fe melts is more complex than the typical simple liquid structure and the simple icosahedral short-range order.The resuits of the pair analysis technique show that the icosahedral short-range order may grow with the decrease of the temperature and may become more prevalent in the undercooled state.