RE-X二元合金相图的热力学数据库

利用CALPHAD方法,采用亚正规溶体模型、亚点阵模型以及理想气体模型来描述RE-X(Ag,Bi,Cr,Mn,Mo,V,Zn)中二元系各相的Gibbs自由能,并结合相平衡及热力学性质的实验结果,对Ag-RE(RE:Sc,Y Nd,Sm,Gd,.Tb,Ho,Er)、Bi-RE(RE:Nd,Tm,Er,Ho,Pr,Gd)、...     

Mo-Re和W-Re二元体系的热力学和相图优化

应用CALPHAD方法和Thermo-Calc软件,对Mo-Re和W-Re二元系进行了热力学优化,得到了与试验数据及第一性原理计算结果吻合较好的结果。由于Mo-Re和W-Re体系较为相似,同时进行优化,尤其是对Re端际的补充熵进行了统一,建立了更为合理的Mo-Re和W-Re相图。     

锌基合金热力学和相图数据库的建立

利用Visual Basic 6.0软件开发了一套锌基合金体系热力学和相图数据库系统,用于收集、整理锌基合金体系的热力学和相图相关信息.利用该软件系统可以实现对锌基合金体系热力学和相图数据的排序、查询和打印等功能,也可实现数据库的实时更新.探讨了如何实现该软件系统的各项功能,解决了锌合金体系热力学和相图数据人工查询的低效率问题,该数据库软件在锌合金的改性和新型锌合金的设计与开发应用中具有一定使用价值.     

Nd-Fe-B-Dy四元系热力学数据库的建立及其合金设计

本研究利用CALPHAD方法,采用合理的热力学模型,热力学优化和计算了Nd-Dy、Dy-B二元系和Fe-B-Dy、Dy-Fe-Nd、B-Dy-Nd三元系的相图,并利用文献报道的其他子二元系和三元系的热力学参数,充分考虑了热力学模型的统一性和参数的兼容性,建立了Nd-Fe-B-Dy四元系合金的热力学数据库,并应用该数据库,预测了Nd-Fe-B-Dy四元合金Nd16-xDyxFe77B7 (x≤5 at.%)的纵截面相图;同时还分析了一系列不同Dy含量的永磁合金在平衡凝固下各相相分数随温度的变化情况。这些计算信息对掺镝NdFeB永磁合金的组织设计以及制备工艺参数的选择具有重要的指导意义。     

Au-Pt二元合金的热力学评估(英文)

基于最近实验测得的Au-Pt二元体系相平衡数据,利用Calphad方法重新评估Au-Pt二元体系的热力学参数。采用亚正规溶体模型Redlich-Kister等式描述液相和面心立方相的Gibbs自由能。考虑热力学第三定律的限定,以再现相平衡数据和固相热力学性质,包括活度和混合焓,优化Au-Pt二元系统热力学参数。优化结果表明:Au-Pt合金系统的溶解度间隙边界向富Au侧偏移,其顶点位置在1200°C,Au-56%Pt。     

Ce-La-O体系相图热力学及应用(英文)

采用实验测量和热力学计算相结合的方法,系统研究Ce-La-O体系相图热力学和Ce-La合金的氧化反应过程。制备一系列不同成分的CeO2-LaO1.5混合物并对其进行X-射线衍射分析,获得了LaO1.5与CeO2在1273K时的相互固溶度;利用该研究测量以及文献报道的实验数据,优化了CeO2-LaO1.5体系相图;结合已有的Ce-O和La-O体系热力学描述,计算了Ce-La-O体系状态图并解释了Ce-La合金的氧化反应过程,发现只要La含量不超过80%,Ce-La合金被氧化后均形成CeO2为基的固溶体。     

锇铱铑钌二元合金相图的研究进展(1976～1985)

1.前言在文献[1]中,由Ir、Os、Rh、Ru组成的二元系相图有105个,其中Os二元系只有15个。十年来,铂、钯二元系相图的研究仍然很少。Ir、Os、Rh、Ru二元系相图新增加14个,其研究有所发展的17个,由国际相图协会组织评价的有14个。这些体系的具体分属和文献[1]的比较见表1。     

Ag－Cu－RE合金相图中的固溶度及成相规律

根据对Ａｇ－Ｃｕ－ＲＥ（ＲＥ＝Ｃｅ，Ｎｄ，Ｓｍ，Ｔｂ，ＲＥ≤３４ａｔ％）三元系的９个等温截面的研究结果，探讨了它们的固溶度及成相规律。     

Thermodynamic database of the phase diagrams in the Mg-Al-Zn-Y-Ce system

The Mg-Al-Zn-Y-Ce system is one of the key systems for designing high-strength Mg alloys. The purpose of the present article is to develop a thermodynamic database for the Mg-Al-Zn-Y-Ce multicomponent system to design Mg alloys using the calculation of phase diagrams （CALPHAD） method, where the Gibbs energies of solution phases such as liquid, fcc, bcc, and hcp phases were described by the subregular solution model, whereas those of all the compounds were described by the sublattice model. The thermodynamic parameters describing Gibbs energies of the different phases in this database were evaluated by fitting the experimental data for phase equilibria and thermodynamic properties. On the basis of this database, a lot of information concerning stable and metastable phase equilibria of isothermal and vertical sections, molar fractions of constituent phases, the liquidus projection, etc., can be predicted. This database is expected to play an important role in the design of Mg alloys.     

Thermodynamic Assessment of the Ru-Zr Binary System

The Ru-Zr system has been assessed by means of the Calphad approach. The solution phases (Liquid, (Ru), and were modeled with the sublattice formalism and the excess term of the Gibbs energy with the Redlich-Kister equation. The intermetallic compounds and RuZr, which have homogeneity ranges, were treated as the formula and by a two-sublattice model with a mutual substitution of Ru and Zr on both sublattices. The calculated phase diagram and the thermodynamic properties of the system are in satisfactory agreement with the experimental data.     

Thermodynamic Database for Phase Diagrams of Mn-RE Binary Alloy Systems

Thermodynamic assessment of Mn-RE (RE: Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, Lu) binary systems has been carried out by means of the calculation of phase diagrams method on the basis of experimental data including phase equilibria and thermodynamic properties. The Gibbs free energies of liquid phase and solid solution phases in the Mn-RE systems were all described by the subregular solution model with the Redlich–Kister formulation, whereas those of intermetallic compounds were described by the sublattice model. Sets of thermodynamic functions with self-consistent parameters leading to satisfactory agreement between calculated results and experimental data were eventually obtained. A primary thermodynamic database for the phase diagrams of the Mn-RE (RE: Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, Lu) binary systems was developed from these essential thermodynamic parameters. This database can be used not only to calculate the phase equilibria and thermodynamic properties of binary Mn-RE systems but also to extrapolate to higher-order systems, which can provide theoretical guidance for design and development of high-performance Mn-RE alloy materials.     

Critical Evaluation and Thermodynamic Optimization of the Binary Systems in the Mg-Ce-Mn-Y System

Critical evaluation and thermodynamic optimization have been carried out for the Mg-Ce, Mg-Mn, Mg-Y, Ce-Mn, Ce-Y, and Mn-Y binary systems. All phase diagrams and thermodynamic data such as enthalpies of mixing, heats of formation, etc., were considered to obtain one set of model parameters of the Gibbs energies of all phases, which can reproduce the experimental data within experimental error limits. For the liquid alloys, the Modified Quasi-chemical Model in the pair approximation was used to treat short-range-ordering.     

Thermodynamic assessment of ZnO-SiO2 system

ZnO-containing slags are common in pyrometallurgical processing of the base metals and steel. This caused the interest to the thermodynamics of the ZnO-SiO₂ system. A complete literature survey, critical evaluation of the available experimental data and a thermodynamic optimization of the phase equilibria and thermodynamic properties of the system ZnO-SiO₂ at 1.013×10⁵ Pa are presented. The molten oxide was described as an associate solution. The properties of liquid were reassessed and enthalpy term of the Gibbs energy of solid Zn₂SiO₄ was re-fitted to be compatible with the new data in the willemite primary phase field. The thermodynamic data set agrees well with the recent experimental observations. It can be used for predicting, e.g., the thermodynamic properties and the domains of the phase diagram, like critical point of the liquid miscibility gap, with a better accuracy than using the previous assessments. A set of optimized model parameters were obtained, reproducing the reliable thermodynamic and phase equilibrium data within their experimental errors from 298 K to liquidus temperatures, over the entire composition range. The created database can be used in a Gibbs energy minimization software to calculate the thermodynamic properties and the phase diagram sections of interest.     

Thermodynamic assessment of Cu-Cd system

A thermodynamic assessment of the Cu-Cd system has been carried out by CALPHAD technique.The liquid phase, FCC_A1(Cu)and HCP_A3(Cd)terminal phases are described by a simple substitutional model,their excess Gibbs energy is formulated with the Redlich-Kister expression.The system contains four intermediate compounds,includingβ(Cu2Cd),γ(Cu4Cd3), δ(Cu5Cd8)andε(Cu3Cd10).Theδphase is described by a two-sublattice model and the other three intermediate phases are treated as stoichiometric phases.The optimization is carried out in the Thermo-Calc package.A set of self-consistent thermodynamic parameters are obtained.The calculated phase diagram and thermodynamic properties agree well with the available experimental data.     

Thermodynamic Study of Liquid,Crystalline and Quasi-Crystalline Al-Mn Phases

Thermodynamic properties of liquid, intermetallic, and quasi-crystalline phases of the Al-Mn system have been studied using two experimental techniques: integral effusion method and Knudsen-cell mass spectrometry. The functions of the liquid phase followed the laws of associated solution and indicated that three type complexes, AlMn, Al₂Mn, and Al₅Mn, existed in the melt. Phase equilibria calculated using this model and the intermetallic compounds thermodynamic characteristics were in close agreement with phase diagram. The decagonal phase was found to be more stable than the icosahedral quasi-crystals. The calculated enthalpies of the quasi-crystalline phase transformation to the equilibrium crystals were close to the available literature information. The difference between the Gibbs energies of both type quasi-crystals and equilibrium crystalline compositions increases with decreasing temperature. This evidence favors the conclusion that the stabilization of quasi-crystals is entropic in nature and that the quasi-crystalline state, similar to the glassy state in metallic alloys, is only intermediate between liquid and crystals. The conditions of the quasi-crystals formation were found to be closely related to a certain type of the chemical short-range order in liquid, namely to significant mole fraction of the Al₅Mn associative complexes.     

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.