Thermodynamic assessment of the Al-Pt binary system

The calculation of phase diagram (CALPHAD) technique has been used to carry out the thermodynamic assessment of the Al-Pt binary system. Seven intermetallics are considered as stable phases in addition to the terminal solid solutions. The set of Gibbs energy functions with optimized parameters is used to calculate the Al-Pt binary phase diagram as well as the thermodynamic properties in good agreement with the experimental results.     

Thermodynamic assessment of the Cu-In binary system

On the basis of thermodynamic properties and phase diagram data, the Cu-In binary system was thermodynamically assessed. The phases in this system were modeled using the Redlich-Kister expression for the Gibbs energies of the solution phases, adopting three-sublattice models for γ and η′, and assuming stoichiometric compounds for other intermetallic phases. Then a set of consistent parameters was obtained by the CALPHAD method, by which reasonable agreement can be realized between the thermodynamic properties for various phases and phase relations of this system.     

Thermodynamic assessment of the Fe-U binary system

The Fe-U system is one of the binaries of the U-Fe-Zr-O quaternary system that is important for a safe nuclear program. A new thermodynamic assessment of Fe-U is presented, taking into account some recent thermodynamic measurements: enthalpy of formation and of melting as well as heat capacities for both intermetallic compounds Fe₂U and FeU₆. The calculated phase diagram and thermodynamic data generally agree very well with the experimental values. The calculated temperature of the peritectic transformation [FeU₆ ↔ liquid + bcc-U] is equal to 1104 K, which is higher than in the previous assessments, but in agreement with Labroche’s value. However, the experimental melting enthalpy of FeU₆ is not reproduced by the present set of thermodynamic parameters.     

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 assessment of the Fe-U binary system

The Fe-U system is one of the binaries of the U-Fe-Zr-O quaternary system that is important for a safe nuclear program. A new thermodynamic assessment of Fe-U is presented, taking into account some recent thermodynamic measurements: enthalpy of formation and of melting as well as heat capacities for both intermetallic compounds Fe₂U and FeU₆. The calculated phase diagram and thermodynamic data generally agree very well with the experimental values. The calculated temperature of the peritectic transformation [FeU₆ ↔ liquid + bcc-U] is equal to 1104 K, which is higher than in the previous assessments, but in agreement with Labroche’s value. However, the experimental melting enthalpy of FeU₆ is not reproduced by the present set of thermodynamic parameters.     

Thermodynamic assessment of the Cu-In binary system

On the basis of thermodynamic properties and phase diagram data, the Cu-In binary system was thermodynamically assessed. The phases in this system were modeled using the Redlich-Kister expression for the Gibbs energies of the solution phases, adopting three-sublattice models for γ and η′, and assuming stoichiometric compounds for other intermetallic phases. Then a set of consistent parameters was obtained by the CALPHAD method, by which reasonable agreement can be realized between the thermodynamic properties for various phases and phase relations of this system.     

Thermodynamic assessment of the Nd–Zn binary system

On the basis of available experimental information, the Nd–Zn binary system has been thermodynamically optimized using the CALPHAD method. The solution phases, liquid, bcc and dhcp, were treated as substitutional solutions, while the intermediate compounds, NdZn, NdZn₂, NdZn₃, Nd₃Zn₁₁, Nd₁₃Zn₅₈, Nd₃Zn₂₂, Nd₂Zn₁₇ and NdZn₁₁, were described as stoichiometric phases. A set of self-consistent parameters formulating the Gibbs energies of various phases in this binary system was obtained. Most of experimental data on thermochemistry and phase diagram reported in the literatures were satisfactorily reproduced.     

Thermodynamic assessment of the Mo–Re binary system

The existing Mo–Re phase diagrams are reviewed and a thermodynamic calculation of the Mo–Re binary system is undertaken. The Gibbs energies are estimated for liquid, bcc (Mo), hcp (Re), σ and χ phases. The liquid, bcc (Mo) and hcp (Re) phases are described by a regular solution model, whereas the σ and χ phases are described respectively by three-sublattice models. For the σ phase, two thermodynamic models are used for calculations and the results are compared. The models take into account the crystallographic structure and similarity between the σ and χ phases. The calculated results remove the ambiguity of the existing phase diagram data and are compared with the experimental data in the literature.     

Thermodynamic assessment of the Cu–Dy binary system

The Cu–Dy binary system has been thermodynamically assessed with CALPHAD approach. The solution phases including liquid, Bcc, Fcc and Hcp were treated as substitutional solution phases, of which the excess Gibbs energies were formulated with Redlich–Kister polynomial functions. The binary intermetallic compounds were treated as stoichiometric phases. A set of self-consistent thermodynamic parameters for describing various phases in this system has been obtained, which can well reproduce the corresponding experimental data.     

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。     

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.     

Fe-Ti二元体系的热力学重新优化(英文)

为提高Fe-Ti二元系外推到三元或多元体系的能力,应用CALPHAD方法重新优化了该二元系。与前人的优化工作相比,重点放在对两个二元金属间化合物Fe2Ti和FeTi的热力学描述上。因目前普遍采用双亚点阵模型来描述C14_Laves相,所以采用双亚点阵模型来描述Fe2Ti相。通过检验包含Fe-Ti二元系的三元体系Fe-Ti边界上Fe2Ti相的均匀化范围进一步证实了Fe2Ti相的相边界。FeTi相具有BCC_B2晶体结构,因而将其处理成为BCC_A2相的有序相,并且用统一的Gibbs 能函数来描述有序和无序相。另外一个特别关注的方面就是重现这两个化合物的实测热容。计算结果与有关相图和热力学性质实验结果的广泛对比显示两者符合得很好,从而证明了所得热力学描述的有效性。