Development of phase diagram calculating codes based on bond order potentials

基于键序势的相图计算代码的开发

• 批准号: 11555161
• 负责人: NISHITANI Shigeto
• 金额: $ 8.83万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555161/
• 关键词: Phase diagram; Frenkel method; Vibrational entropy; bcc-hcp transition; モンテカルロシミュレーション; Quasi-Harmonic近似; 統計モーメント法; Ti; ボンドオーダーポテンシャル; 有限温度; モンテカルロ法; 自由エネルギー; Einstein結晶モデル; タイトバインディング; フルポテンシャルLMTO法; 状態図計算; 遷移金属合金; タイトバインディング理論; モーメント近似

For the purpose of reliable calculations on free energies on elemental p-T diagram and binary phase diagram, we checked the effects of1. many body interactions of enthalpy changes, and2. anharmonic vibrational entropies.1. Many body interactionsThe enthalpy changes arised from the environment dependency of chemical bondings are predicted by bond order potentials based on Tight binding approximation. We developed parallel code and applied them to predict formation enthalpies of dilution limit alloys.2. Anharmonic vibrational entropiesThermal expansion and allotropic phase transitions are controlled by anharmonic effects of vibration entropies, which is reliably estimated by Frenkel method in Monte Cargo simulations. We developed also paralled code and applied it on bcc-hcp transition in Ti.Based on these simulations we also developed new method of reliable prediction on free energy changes of precipitate nucelations.We opened some of these developed codes in public, and the others are in progress.

为了可靠地计算元素p-T图和二元相图上的自由能，我们检验了1。许多机构的相互作用的焓变化，和2.非谐振动熵。多体相互作用在紧束缚近似下，用键级势预测了化学键的环境依赖性引起的焓变。我们开发了并行程序，并将其应用于稀释极限合金的形成过程预测.非谐振动熵热膨胀和同素异性相变受振动熵的非谐效应控制，这是可靠的估计在Monte Cargo模拟的Frenkel方法。我们还开发了并行程序，并将其应用于Ti的bcc-hcp相变模拟，在此基础上，我们还开发了一种新的预测沉淀成核自由能变化的可靠方法，其中一些程序已公开，另一些程序正在开发中。

项目成果

S. Nishitani, M. Aoki, S. Muto: "The Problems of Defects Physics--Solve them and grasp the Nature!"Yoshioka-Shoten. (2003)

S. Nishitani、M. Aoki、S. Muto：“缺陷物理问题——解决它们并掌握本质！”吉冈书店。

F.Oba: "Energetics of native defects in ZnO"J.Appl.Phys.. (in press). (2001)

F.Oba：“ZnO 天然缺陷的能量学”J.Appl.Phys..（出版中）。

F.Oba: "Electronic structure calculation of symmetric tilt boundaries in ZnO"Ceramic Transactions. (in press). (2001)

F.Oba：“ZnO 中对称倾斜边界的电子结构计算”Ceramic Transactions。

F.Oba: "Ab initio study of symmetric tilt boundaries in ZnO"Phys.Rev.B. 63. 045410 (2001)

F.Oba：“ZnO 中对称倾斜边界的从头算研究”Phys.Rev.B。

Y.Koyama: "Evaluation of Migration Energy of Lithium Ions in Chalcogenides and Halides by First Principles Calculation"Materials Trans.. 43. 1460-1463 (2002)

Y.Koyama：“通过第一原理计算评估硫属化物和卤化物中锂离子的迁移能”Materials Trans.. 43. 1460-1463 (2002)