Fe-M和Ti-M(M=Li,Na,K)体系的相图热力学研究

基于已有的试验数据,采用相图计算法对Fe-M和Ti-M(M=Li,Na,K)体系进行相图热力学研究。通过热力学优化计算获得了一套描述液相、(αFe)、(γFe)、(δFe)、(αTi)、(βTi)、(Li)、(Na)和(K)相的热力学参数。Ti-Li、Ti-Na和Ti-K体系中的气相视为理想气体。计算数据与试验相图数据对比表明,本文获得的热力学参数能准确描述试验相平衡数据。     

热力学优化Bi-Ni二元系

基于文献报导的实验数据,采用相图计算（CALPHAD）方法,热力学优化了Bi-Ni二元系相图。该二元系的液相、fcc_A1（Ni）相和rhombohedral_A7（Bi）相用替换溶液模型来描述,其过剩吉布斯自由能用Redlich-Kister多项式来表达。考虑到晶体结构（NiAs型）以及与多组元体系热力学数据库的兼容性,中间化合物BiNi相采用亚点阵模型：（Bi）（Ni,Va）（Ni,Va）;Bi3Ni相处理为化学计量比化合物。最后,通过优化该二元系实测的相图和热力学数据,获得一组能够表达各相吉布斯自由能的自洽的热力学参数。根据这些热力学参数计算的相图和热力学数据与报导的实验数据吻合良好。     

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。     

Ir-Pt二元相图的优化计算

利用Pandat相平衡热力学计算软件优化和计算了Ir-Pt二元相图。采用SGTE(Science Group Thermodata Europe)数据库中的表达式描述纯组元(Ir和Pt)的Gibbs自由能,采用固溶体相热力学模型描述Ir-Pt二元体系中的液相和固溶体相。利用Pandat中的PanOptimizer优化平台,并结合最新的相关数据,对Ir-Pt二元体系中各相的参数进行了优化,优化得到了Ir-Pt二元体系中各相的热力学参数。利用优化的热力学参数对Ir-Pt二元合金相图进行了计算,计算得到的相图表明调幅分解的临界点为995℃、50%Ir(摩尔分数)左右,与SGTE贵金属合金数据库所提出的Ir-Pt二元体系在相图和热力学数据上都较为吻合。     

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.     

Ni—Zr二元相图计算

优化和计算了ＮｉＺｒ二元相图。液相用缔合物模型、端际固溶体用替换溶液模型描述，Ｎｉ５Ｚｒ和Ｎｉ１０Ｚｒ７则分别选用了（Ｎｉ）１（Ｎｉ，Ｖａ）４（Ｎｉ，Ｚｒ）１和（Ｎｉ，Ｚｒ）１０Ｚｒ７的亚点阵模型。计算结果与大部分相图和热力学数据相吻合     

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。     

BaO-MgO二元系相图优化计算研究

在对BaO-MgO二元系热力学数据评估的基础上,采用Thermo-Calc软件对该体系相图进行优化计算.采用规则溶液模型,获得了较完整的BaO-MgO二元系相图和该体系较完整的热力学数据.还对该二元系的混合焓及组元活度进行了讨论.通过与实验数据进行比较,在富BaO端与实验结果基本吻合;在富MgO端,采用了最新的MgO熔点温度,获得了更加合理的液相线.     

Mo-RE二元合金相图的热力学数据库

利用CALPHAD方法,选择和建立合理的热力学模型,并结合相平衡及热力学性质的相关实验信息,对Mo-RE (RE: Ce, Pr, Nd, Sm, Eu, Tb, Ho, Er, Tm, Yb, Lu)各二元系相图进行了热力学优化与计算。其中,液相和端际固溶体相的Gibbs自由能采用亚正规溶体模型描述,气相的Gibbs自由能采用理想气体模型描述。计算结果与实验数据取得了良好的一致性,最终得到了一组自洽的合理描述Mo-RE二元系各相自由能的热力学参数,建立了Mo-RE (RE: Ce, Pr, Nd, Sm, Eu, Tb, Ho, Er, Tm, Yb, Lu)二元合金相图的热力学数据库。该热力学数据库可以提供相平衡及热力学性质等多种信息,为外推计算三元以及更多组元体系的相平衡提供理论基础,并为相关体系的合金设计及制备提供重要的理论指导。     

ZnO-SiO_2体系的热力学评价（英文）

含ZnO炉渣是贱金属和钢的火法冶金过程中常见的炉渣,这导致人们对于ZnO-SiO_2体系热力学的兴趣。本文作者对ZnO-SiO_2体系进行全面的文献评述,对现有实验数据进行批判性评价,对体系相平衡进行热力学优化,给出了ZnO-SiO_2体系在1.013×10~5Pa总压力下的热力学性质。将熔融氧化物视为缔合溶液,重新评估了液相的性质。对固体Zn_2SiO_4吉布斯自由能的焓项重新进行拟合,使之与硅锌矿初晶区的新数据相符。所得热力学数据与新近的实验观测结果吻合良好。这些结果可用于预测热力学性质和相图中的相区,如液相混溶区的临界点,预测准确度优于以往的方法。获得了一组优化的模型参数,在整个组成范围内,温度从298 K到液相线温度,重新生成了可靠的热力学和相平衡数据,其误差在实验误差范围内。建立的数据库可用于Gibbs自由能最小化软件中热力学性质和有关相图截面的计算。     

Thermodynamic evaluation of the Al-H system

The thermodynamic properties of the Al-H system were assessed using models for the Gibbs energy of the individual phases, including the metastable hydride AlH₃ phase. The model parameters were obtained through optimization by best fitting to selected experimental data. Particular attention was paid to hydrogen solubility in liquid and face-centered-cubic (fcc) Al. It was shown that the hydrogen can be treated as an ideal gas under normal conditions. The hydrogen solubility in liquid and fcc Al can be described very well with a regular solution model for liquid and fcc. The present calculations show satisfactory agreement with most experimental data for hydrogen solubility in fcc Al and selected data for hydrogen solubility in liquid Al, qualifying the extension of this binary model to higher-order Al-H-bearing systems.     

A thermodynamic assessment of the Al-Cu-Mg ternary system

A thermodynamic assessment of the Al-Cu-Mg ternary system is presented. The Gibbs energies for the liquid and solid solution phases were modeled using the Redlich-Kister polynomial and the Wagner-Schottky model represented by the compound-energy formalism. The model parameters were obtained after fitting to previously critically assessed experimental phase diagram and thermodynamic data available in the literature. The thermodynamic functions and phase diagram calculated using the model parameters describe quite well the known experimental information. The complete set of Gibbs energies for all phases appearing in this system enables the calculation of thermodynamic values as a function of composition and temperature even for those ranges where no experimental information is available.     

Thermodynamic assessments of the Cu–Th and Mo–Th systems

The thermodynamic assessments of the Cu–Th and Mo–Th binary systems were carried out by using Calculation of Phase Diagrams (CALPHAD) method on the basis of the experimental data including the thermodynamic properties and phase equilibria. The Gibbs free energies of the liquid, bcc, and fcc phases are described by the subregular solution model with the Redlich–Kister equation and those of the four intermetallic compounds Cu₆Th, Cu_3.6Th, Cu₂Th and CuTh₂ in the Cu–Th binary system were described by the sublattice model. A set of self-consistent thermodynamic parameters are obtained, and the calculated phase diagrams and thermodynamic properties are presented and compared with the experimental data from literatures. The calculated thermodynamic properties as well as phase diagrams are in good agreement with the experimental data.     

Assessment of the Te-Tl (tellurium-thallium) system

The optimized thermodynamic data for the Te- TI binary system have been obtained by the computer operated least squares method from measured data. The Gibbs energy of the liquid phase was modeled as a two- sublattice model for ionic melt after Hillert.³¹ The intermediate compounds, Te₃Tl{2}and TeTl, were treated as stoichiometric phases, and the nonstoichiometric γ phase was expressed as a sublattice model. A strong tendency for chemical short- range order in the liquid state at the composition close to TeTh was confirmed by calculated results, but the existence of the TeTh phase was not justified. The experimental thermodynamic and phase diagram data were closely reproduced by the optimized thermodynamic data. Parameters describing the Gibbs energies of all the phases in this calculation and the calculated phase diagram and thermodynamic functions are presented and compared with experimental information.     

Assessment of the Te-Tl (tellurium-thallium) system

The optimized thermodynamic data for the Te- TI binary system have been obtained by the computer operated least squares method from measured data. The Gibbs energy of the liquid phase was modeled as a two- sublattice model for ionic melt after Hillert.³¹ The intermediate compounds, Te₃Tl{2}and TeTl, were treated as stoichiometric phases, and the nonstoichiometric γ phase was expressed as a sublattice model. A strong tendency for chemical short- range order in the liquid state at the composition close to TeTh was confirmed by calculated results, but the existence of the TeTh phase was not justified. The experimental thermodynamic and phase diagram data were closely reproduced by the optimized thermodynamic data. Parameters describing the Gibbs energies of all the phases in this calculation and the calculated phase diagram and thermodynamic functions are presented and compared with experimental information.     

Thermodynamic analysis and phase equilibria calculations of pb-zn, sn-zn, and pb-sn-zn systems

Thermodynamic properties of liquid and solid phases in the Pb-Zn, Sn-Zn, and Pb-Sn-Zn systems were assessed using a quasi sub-subregular solution model. The model parameters for different phases were obtained by simultaneous optimization with respect to the available thermodynamic and phase equilibrium data. Phase diagrams and thermodynamic data were then calculated and compared with the experimental/assessed data.     

Thermodynamic assessment of the Ni-Sb binary system

The Ni-Sb binary alloy system was thermodynamically assessed using CALPHAD approach in this article.Excess Gibbs energies of solution phases,liquid and fcc phases,were formulated using the Redlich-Kister expression.The intermediate phases were modeled by the sublattice model with (Ni,Va)0.5(Ni,Sb)0.25(Ni)0.25 for Ni3Sb_HT phase and (Ni,Va)0.3333(Sb)0.3333(Ni,Va)0.3333 for NiSb phase.The other phases including Ni3Sb,Ni7Sb3,and NiSb2 were treated as stoichiometric compound owing to their narrow composition ranges.Based on the reported thermodynamic properties and phase diagram data,the thermodynamic parameters of these phases were optimized,and the obtained values can reproduce the available experimental data well.     

Thermodynamic and Experimental Study of the Mg-Sn-Ag-In Quaternary System

Phase equilibria in the Mg-rich region of the Mg-Sn-Ag ternary system were determined by quenching experiments, differential scanning calorimetry, electron probe micro-analysis, and X-ray diffraction techniques. No ternary compounds were found in the studied isothermal sections. A critical evaluation of the available experimental data and a thermodynamic optimization of the Mg-Sn-Ag-In quaternary system were carried out using the calculation of phase diagrams method. The modified quasichemical model in the pair approximation was used for the liquid solution, which exhibits a high degree of short-range order. The solid phases were modeled with the compound energy formalism. All available and reliable experimental data were reproduced within experimental error limits. A self-consistent thermodynamic database was constructed for the Mg-Sn-Ag-In quaternary system, which can be used as a guide for Mg-based alloys development.     

Prediction of the formation enthalpies of Bi–Cd–Ga–In–Pb–Sn–Zn liquid alloys by binary infinitely dilute enthalpies

The molecular interaction volume model (MIVM) is used to predict the formation enthalpies of Bi–Cd–Ga–In–Sn–Zn and Bi–Cd–Ga–In–Pb–Sn–Zn liquid alloys, using only the infinitely dilute enthalpies of binary systems and the coordination numbers of the constituent elements in liquid alloys. In addition, the infinitely dilute enthalpies of binary system were obtained by Miedema's theory without requiring experimental data. The results are compared with the experimental data and calculated values using the Hoch–Arpshofen model (HAM), the results indicate that the model is reliable as well as being convenient.