First-Principles Calculation of Ternary Phase Diagrams

三元相图的第一性原理计算

• 批准号: 9114646
• 负责人: Juan Sanchez
• 金额: $ 23.7万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-12-01 至 1995-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9114646&HistoricalAwards=false
• 关键词: First; Principles; Calculation; Ternary; Phase

A first-principles electronic theory of alloy phase stability is used to investigate the thermodynamic properties and the temperature-composition phase diagrams of binary and ternary systems. The emphasis of this study is on the development and testing of computational schemes - based on quantum mechanical calculations of binding energies, vibrational entropies and configurational entropies - in order to predict solid state phase stability. Electronic structure calculations of the total energy of ordered compounds are carried out using the Linear Muffin-Tin Orbital and the Local Density Approximations. The Liner Muffin-Tin Orbitals total energy calculations are used to obtain multiatom effective chemical interactions, equilibrium lattice constants, bulk moduli, Debye temperatures, Gruneisen Constants and expansion coefficients of configurationally ordered compounds. These calculations provide all information necessary for the computation of equilibrium phase diagrams. Ternary equilibrium and metastable phase diagrams will be calculated for a number of important alumindes to establish trends which may offer predictive results. %%% Calculations of accurate alloy phase diagrams have usually been based on experimental input and phenomenological models. The resulting phase diagrams were sometimes lacking in predictive capability. The research proposed here will calculate phase diagrams based on first-principles; essentially providing only the properties of the atoms making up the alloy. The calculation of first-principles phase diagrams is an important step in the design of new materials having desired properties. The present work will develop techniques to do these calculations for the more difficult case of ternary alloys.

合金相稳定性的第一性原理电子理论 用于研究热力学性质和 二元和三元温度-组成相图 系统. 本研究的重点是发展和 测试计算方案-基于量子力学 结合能、振动熵和 构型熵-为了预测固态相 稳定 总能量的电子结构计算 有序化合物进行使用线性松饼锡 轨道和局部密度近似。 The Liner Muffin-Tin 利用轨道总能量计算得到了多原子 有效的化学相互作用，平衡晶格常数， 体积模量、德拜温度、格吕尼森常数和膨胀 构型有序化合物的系数。 这些 计算提供了计算所需的所有信息 平衡相图。 三元平衡和亚稳 相图将计算一些重要的 铝化物，以建立可以提供预测结果的趋势。 %%% 精确的合金相图的计算通常是 基于实验输入和现象学模型。 的 所得相图有时缺乏预测性， 能力。 这里提出的研究将计算相位 基于第一原理的图表;基本上只提供 组成合金的原子的性质。 的计算 第一性原理相图是设计中的重要步骤 具有所需性能的新材料。 目前的工作将 开发技术来做这些计算， 三元合金的情况。