CALCULATION OF THERMODYNAMIC PROPERTIES AND PHASE DIAGRAM OF TERNARY MOLTEN SALT SYSTEM NaCl-CaCl_2-SrCl_2 BY USE OF COMPUTOR

本文利用 CaCl-SrCl_2相图中,固相有一个溶解间断区(miscibility gap)的信息,用亚正规溶液模型计算了该二元系液相和固相的 Gibbs 自由能.运用 Toop方程的变通式即最近 Hillert.M.提出的新的非对称方法,由组成 NaCl-CaCl_2-SrCl_2三元系的二元系热力学性质预示了该三元系液相的 Gibbs 自由能,进而用计算机计算了三元液相中各组元的偏克分子 Gibbs 自由能和活度系数.由三元液相中组元 NaCl,CaCl_2和 SrCl_2的过剩偏克分子 Gibbs 自由能,根据相平衡原理,用计算机计算了该三元系的相图.计算结果对于钠电解的实践和盐湖资源的综合利用有实际意义.亚正规溶液模型和新的非对称方法可望适合于计算一系列有潜在重要性的电荷不对称熔盐体系的相图.如对 Na,Ti,Mg,Ce 电解及熔融氯化脱水制取无水氯化镁有实际意义的 NaCl-CaCl_2-BaCl_2,NaCl-SrCl_2-BaCl_2,NaCl-CaCl_2-MgCl_2,KCl-CaCl_2-MgCl_2,KCl-NaCl-CeCl_3等三元相图.     

三元熔盐系NaCl-CaCl_2-SrCl_2的热力学性质和相图的计算机计算

本文利用 CaCl-SrCl_2相图中,固相有一个溶解间断区(miscibility gap)的信息,用亚正规溶液模型计算了该二元系液相和固相的 Gibbs 自由能.运用 Toop方程的变通式即最近 Hillert.M.提出的新的非对称方法,由组成 NaCl-CaCl_2-SrCl_2三元系的二元系热力学性质预示了该三元系液相的 Gibbs 自由能,进而用计算机计算了三元液相中各组元的偏克分子 Gibbs 自由能和活度系数.由三元液相中组元 NaCl,CaCl_2和 SrCl_2的过剩偏克分子 Gibbs 自由能,根据相平衡原理,用计算机计算了该三元系的相图.计算结果对于钠电解的实践和盐湖资源的综合利用有实际意义.亚正规溶液模型和新的非对称方法可望适合于计算一系列有潜在重要性的电荷不对称熔盐体系的相图.如对 Na,Ti,Mg,Ce 电解及熔融氯化脱水制取无水氯化镁有实际意义的 NaCl-CaCl_2-BaCl_2,NaCl-SrCl_2-BaCl_2,NaCl-CaCl_2-MgCl_2,KCl-CaCl_2-MgCl_2,KCl-NaCl-CeCl_3等三元相图.     

Au-Ag-Al系相图的热力学优化和计算

使用计算相图方法(CALPHAD)计算Au-Ag-Al的三元相图时,三个边际二元相图(Au-Al,Au-Ag,Ag-Al)的准确性对三元相图的计算有很大的影响,目前Au-Al边际二元相图存在着一定的矛盾。在综合评估Au-Al体系实验数据的基础上,优化和计算了Au-Al合金体系的平衡相图,使用置换式溶体溶液模型描述Au-Al体系中液相、Bcc和Fcc相的吉布斯自由能,分别用亚点阵模型(Al)(Au)4、(Al)3(Au)8、(Al)(Au)2、(Al)(Au)和(Al,Au)2(Al,Au)描述AlAu4、Al3Au8、AlAu2、AlAu和Al2Au相,通过Pandat软件优化得到一组各相的热力学参数,计算得到的Au-Al相图与实验数据和热力学数据相吻合。结合Au-Ag和Ag-Al的热力学参数,计算了Au-Ag-Al液相面投影图和等温截面图,液相面投影图显示该三元系存在8个四相平衡反应,对Au-Ag-Al合金的研究具有指导意义。     

CONSTRUCTION OF MOLTEN SALT PHASE DIAGRAMS BY COMBINATION OF CALCULATION WITH MEASUREMENT

本文阐述了相图计算的基本原理和确定体系中各相的全摩尔和偏摩尔过剩自由能的方法,特别是由二元系性质预示三元系性质的几何模型.在指出相图计算的意义和局限性的同时,阐明了理论计算和实验测定相结合是构筑熔盐相图的最佳方法及该方法的主要步骤.     

理论计算和实验测定相结合构筑熔盐相图

本文阐述了相图计算的基本原理和确定体系中各相的全摩尔和偏摩尔过剩自由能的方法,特别是由二元系性质预示三元系性质的几何模型.在指出相图计算的意义和局限性的同时,阐明了理论计算和实验测定相结合是构筑熔盐相图的最佳方法及该方法的主要步骤.     

熔盐溶液的统计理论——第三部分 三元同离子系的相平衡

根据我们以前提出的熔盐溶液的统计模型,和零级近似规则溶液理论,导出了AB-AC-AD型和A_2B-AC-AD型三元熔盐相图的液相面方程式。计算结果用若干三元相图进行了验证,结果符合较好。对其他类型的三元同离子系相图,则讨论了溶解能参数和相图几何特征的关系。     

高性能铜合金热力学数据库的开发及其在材料设计中的应用

利用相图计算(CALPHAD)方法,采用亚规则溶体模型描述溶体相的吉布斯自由能,采用亚点阵模型描述金属间化合物和有序相的吉布斯自由能,并结合相平衡和热力学性质的实验数据,优化与计算Cu-X二元系以及Cu-Fe、Cu-Ni、Cu-Cr、Cu-Co、Cu-Mo和Cu-W基各三元系的相图,获得自洽性良好的热力学参数,并建立铜合金热力学数据库。该数据库可以提供稳定和亚稳的相图计算、相分数计算、液相面计算、热力学性质的计算等多种信息,为外推计算铜基多元合金系的相平衡提供理论基础,并为高性能铜合金材料的设计及制备提供重要的理论指导。     

STATISTICAL THEORY OF MOLTEN SALT SOLUTIONS Ⅲ. PHASE EQUILIBRIUM OF TERNARY HOMO-IONIC SYSTEMS

根据我们以前提出的熔盐溶液的统计模型,和零级近似规则溶液理论,导出了AB-AC-AD型和A_2B-AC-AD型三元熔盐相图的液相面方程式。计算结果用若干三元相图进行了验证,结果符合较好。对其他类型的三元同离子系相图,则讨论了溶解能参数和相图几何特征的关系。     

Ti—Al—Nb三元系中α／β及α／γ相平衡的热力学计算

对三元系不同结构相平衡进行了巨势法分析。确定了三元系不同结构相平衡的巨势法计算方法，采用亚正规溶体模型描述Ti-Al-Nb三元系中α，β和γ相的Gibbs自由能，由Ti-Al,Al-Nb和Nb-Ti二元系及Ti-Al-Nb三元系相平衡数据。计算了相互作用参数IAlNb^α,INbTi^α,ITiAl^β,IAlNb^βINbTi^β,ITiAl^γ,IAlNb^γ和INbTi^γ，利用获得的热力学参数，运用巨势法对Ti-Al-Nb三元系1423-1673K范围内α/β及α/γ相平衡进行了计算，计算结果与实测相图吻合得很好，证明本方法是可行的，获得的相互作用参数值是合理的。     

分子动力学模拟Pb-Au合金的热力学性质

采用分子动力学方法模拟Pb8Au2和Pb9Au1两种合金体系的热力学性质。计算不同温度下合金体系的生成焓、生成自由能和过剩自由能,同时计算合金的结合能,从宏观和微观角度分析二元合金原子间相互作用,得到的计算结果与实验数据吻合得很好。     

Computer generation of binary and ternary phase diagrams via a convex hull method

A rapid computational technique for determining equilibrium phase diagrams of multicomponent systems by constructing the convex hull of the free energy surface is introduced. Rather than calculating tangent lines or planes, this method guarantees a convex representation of the equilibrium free energy surface on a discrete set of points in composition space. Although the accuracy of these phase diagrams is limited by the spacing of points, there are no restrictions on the number or types of free energy functions that may be considered; functions with singular or unknown derivatives may even be used. This method is then applied to generate several model binary and ternary phase diagrams. This paper was presented at the International Phase Diagram Prediction Symposium sponsored by the ASM/MSD Thermodynamics and Phase Equilibria Committee at Materials Week, October21–23,1991, in Cincinnati, Ohio. The symposium was organized by John Morral, University of Connecticut, and Philip Nash, Illinois Institute of Technology.     

Mo-Si-C系金属间化合物Mo_5Si_3C Gibbs生成自由能估算

根据最小自由能原理和向下凸曲面性质推导出估算三元系和二元系金属间化合物热力学数据的判断式 ,并以 Mo- Si- C三元系为例 ,估算了三元相 T(Mo5 Si3C)的 Gibbs生成自由能。     

MIC公司的钛白生产及战略

根据最小自由能原理和向下凸曲面性质推导出估算三元系和二元系金属间化合物热力学数据的判断式,并以Mo-Si-C三元系为例,估算了三元相T（Mo5Si3C）的Gibbs生成自由能。     

Thermodynamic calculation of phase diagrams of the 60 common-ion ternary systems containing cations Li,Na, K,Rb, Cs and anions F,Cl, Br,I

The phase diagrams of all 60 possible common-ion ternary alkali halide systems were calculated thermodynamically. The thermodynamic properties of the ternary phases were calculated from the optimized properties of the binary subsystems, which were obtained from previously reported critical evaluations of binary data. Calculated ternary phase diagrams are compared with experimental diagrams in those 47 systems for which the latter are available. In most cases, agreement is within experimental error limits. For five systems, a small empirical correction term was added to the Gibbs energy expression in order to bring the calculated and reported diagrams into coincidence. The calculated ternary diagrams are considered to be the best evaluated diagrams that can be deduced from currently available data. A probable maximum inaccuracy was estimated for each system.     

Thermodynamic calculation of phase diagrams of the 60 common-ion ternary systems containing cations Li, Na, K, Rb, Cs and anions F, Cl, Br, I

The phase diagrams of all 60 possible common-ion ternary alkali halide systems were calculated thermodynamically. The thermodynamic properties of the ternary phases were calculated from the optimized properties of the binary subsystems, which were obtained from previously reported critical evaluations of binary data. Calculated ternary phase diagrams are compared with experimental diagrams in those 47 systems for which the latter are available. In most cases, agreement is within experimental error limits. For five systems, a small empirical correction term was added to the Gibbs energy expression in order to bring the calculated and reported diagrams into coincidence. The calculated ternary diagrams are considered to be the best evaluated diagrams that can be deduced from currently available data. A probable maximum inaccuracy was estimated for each system.     

Cu-Ni-Sn三元系相平衡的热力学计算

基于Cu-Ni-Sn三元系的相平衡和热力学的实验信息,采用亚正规溶体模型描述液相和fcc相的Gibbs自由能,为了预测该体系中bcc相的A2-B2有序-无序转变,bcc相的Gibbs自由能采用双亚点阵模型进行描述.利用CALPHAD(相图计算)方法评估了Cu-Ni-Sn三元系各相的热力学参数,计算的富Cu侧相图和热力学性质与实验数据比较一致.并对该三元系中bcc相的A2-B2有序-无序转变及fcc相的溶解度间隙进行了计算.这些计算结果对利用析出强化以及Spinodal分解开发高强度和高导电性的新型Cu基合金的组织设计具有一定的指导意义.     

从三元混合气氛腐蚀相图到四元热腐蚀相图

三元混合气氛腐蚀相图和四元热腐蚀相图的计算具有相通性。三元体系中,将一凝聚相视为由单质金属和气相中两个组元反应生成,而在四元体系内把凝聚相设为由单质金属、Na-O-S体系中一凝聚相和气相中的两个组元反应而成。通过其反应自由能的变化来衡量判断相图中凝聚相西两组合的平衡线和叁叁组合的三相点。     

基于相场法的Ni0.75Al0.05Fe0.2合金预析出相时效过程（英文）

用微观相场法结合自由能和原子间作用势研究了Ni0.75Al0.05Fe0.2合金在1000K时效中沉淀前期的预析出相的形成和转变过程;分析了沉淀前期预析出相和平衡相的自由能、微结构、成分和相体积分数随时间的变化。研究表明:由于结构接近,原子有序化首先形成非化学计量比预析出相L10,随着时间的延长,预析出相L10逐渐向L12相转变,并逐渐达到化学计量比平衡相L12。且发现此转变过程与自由能和原子间作用势有关,预析出相L10比平衡相L12的自由能高且原子间作用势小,故L10相不稳定且转变为稳定的L12相。     

Experimental Investigation and Thermodynamic Calculation of Phase Equilibria in the Mg-Pb-Sn Ternary System

The phase equilibria of the Mg-Pb-Sn ternary system were investigated using a combined method of electron probe microanalyzer and x-ray diffraction. Three isothermal sections of the Mg-Pb-Sn ternary system at 200, 300 and 400 °C were experimentally established. The phase equilibria of Mg-Pb-Sn ternary system were thermodynamically assessed by using CALPHAD (Calculation of Phase Diagrams) method on the basis of the presently determined experimental data. A consistent set of thermodynamic parameters has been derived for describing the Gibbs free energies of each solution phase and intermetallic compound in the Mg-Pb-Sn ternary system. The calculated phase diagrams and thermodynamic properties in the Mg-Pb-Sn ternary system are in good agreement with experimental data.     

In-Bi-Tl三元系液体合金中成分的活度测定SCIEI

用ZrO_2固体电解质组成氧浓差电池:(-)Re,In,In_2O_3|ZrO_2(Y_2O_3)|In-Bi-Tl,In_2O_3,Re(+),在973—1223K的温变范围内测定了In-Bi-Tl三元系中含Tl量较少的两个mol比(N_(Bi)/N_(Tl))一定的拟二元系合金中In的活度,据实验结果求得合金的过剩自由能。使用作者曾提出的计算式及有关各二元系热力学数据计算了合金中In的活度及过剩自由能。计算值与实验值相当一致。此三元系合金的过剩自由能除在In-Tl二元系相近组成以外都呈负值,极小值在Bi-Tl二元系上。