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。     

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     

Density-Functional-Theory Study of Cohesive,Structural and Electronic Properties of Ni-Sb Intermetallic Phases

This work has its roots in a long-term theoretical research line aimed at developing a complete database with structural, thermodynamic, cohesive and elastic properties of the intermetallic compounds (ICs) of the type Me_aX_b where Me = Cu, Ni and X = In, Sn and Sb. The paper reports the results of an ab initio study of various phases occurring in the Ni-Sb phase diagram, viz., the low-temperature Ni₃Sb (orthorhombic oP8), the high-temperature Ni₃Sb (cubic cF16), Ni₅Sb₂ (monoclinic mC28), NiSb (hexagonal hP4) and the NiSb₂ (orthorhombic oP6) compounds. The molar volume, bulk modulus and its pressure derivative, the electronic density of states (DOS) and the energy of formation from the elements of these compounds are calculated ab initio using the relativistic projected augmented wave (PAW) method implemented in the VASP code. The Local Density Approximation of Ceperley and Alder and the Generalized Gradient Approximation due to Perdew and Wang are adopted to treat the exchange and correlation energies. Detailed comparisons between the current and previously reported theoretical and experimental values are reported.     

Thermodynamic assessment of the Nb-Ge system

The Nb-Ge binary system has been thermodynamically assessed using the CALPHAD (Calculation of Phase Diagrams) approach on the basis of the experimental data of both the phase equilibria and the thermochemical properties. The reasonable models were constructed for all the phases of the system. The liquid and the terminal solid solution phases, Bcc-(Nb) and Diamond-(Ge), were described as the substitutional solutions with Redlich-Kister polynomials for the expressions of the excess Gibbs free energies. The intermediate phases (Nb₃Ge), (Nb₅Ge₃), (Nb₃Ge₂) and (NbGe₂) with homogeneity ranges were treated as the sublattice models Nb_0.75(Ge,Nb,Va)_0.25, Nb_0.5(Nb,Ge)_0.125(Ge,Va)_0.375, (Nb,Ge)_0.222(Nb,Ge)_0.333Nb_0.333(Ge,Va)_0.111 and (Nb,Ge)_0.333(Nb,Ge)_0.667 respectively based on their structure features of atom arrangements. A set of self-consistent thermodynamic parameters for the Nb-Ge system was obtained. Using the present thermodynamic data, the calculation results can reproduce the experimental data well.     

Thermodynamic assessment of the Gd–Sb system

A thermodynamic assessment of the binary Gd–Sb system was performed through the CALPHAD approach (CALculation of PHAse Diagram) based on the evaluation of all phase diagram data and available thermodynamic data in the literature. The liquid, hcp-A3 (αGd) and bcc-A2 (βGd) phases were described by a substitutional solution model. All the intermediate phases, Gd₅Sb₃, Gd₄Sb₃, βGdSb, αGdSb and Gd₁₆Sb₃₉, were treated as stoichiometric compounds. A set of self-consistent thermodynamic parameters of the Gd–Sb system has been obtained. A good agreement is obtained between the experimental and the calculated phase diagrams.     

Thermodynamic properties of the ternary system InSb–NiSb–Sb in the temperature range 640–860 K

The ternary InSb–NiSb–Sb system has been studied by X-ray diffraction and by potentiometry. The electromotive forces (EMF) have been measured in the temperature range 640<T/K<860 by using the following galvanic cell:

with x (0.075<x<0.498) and y (0<y<0.359). The investigated samples are located on the following lines of the Gibbs triangle: InSb–Ni_0.33Sb_0.66, InSb–Ni_0.48Sb_0.52, InSb–NiSb, Sb–(InSb)_0.75(NiSb)_0.25, Sb–(InSb)_{0. 5}(NiSb)_0.5, Sb–(InSb)_0.25(NiSb)_0.75. From these measurements, the values of the partial molar thermodynamic functions (Δμ°_m,In, ΔH°_m,In, ΔS°_m,In) (data at reference pressure p⁰=10⁵ Pa), for the liquid InSb alloy, for the three solid heterogeneous regions InSb–NiSb₂–Sb, InSb–NiSb_1±δ?–NiSb₂, InSb–NiSb_1±δ, for six ternary liquid–solid alloys, have been calculated.     

Phase Equilibria Calculation of the Ga-In-Sb Ternary System

ＰｈａｓｅＥｑｕｉｌｉｂｒｉａＣａｌｃｕｌａｔｉｏｎｏｆｔｈｅＧａＩｎＳｂＴｅｒｎａｒｙＳｙｓｔｅｍＸｉｅＹｕｎ′ａｎ，ＱｉａｏＺｈｉｙｕ，ＸｉｎｇＸｉａｎｒａｎａｎｄＷａｎｇＣｏｎｇ（谢允安）（乔芝郁）（邢献然）（王聪）Ｄｅｐｔ．ｏｆＰｈｙｓ...     

Crystallization kinetics of （Ni0.75Fe0.25）78-xNbxSi10B12 （x = 0, 5） amorphous alloys

Amorphous ribbons of （Ni0.75Fe0.25）78-xNbxSi10B12 （x = 0, 5） were prepared by a single roller melt-spinning technique in air atmosphere. The crystallization kinetics of the alloys were investigated by means of continuous heating, and the activation energies of the alloys were calculated using Kissinger plot method and Ozawa plot method on the basis of differential thermal analysis data. The crystallization products were analyzed by X-ray diffraction. After the （Ni0.75Fe0.25）78Si10B12 amorphous alloy was annealed at the temperatures 715 and 745 K, a single phase of γ-（Fe, Ni） solid solution with grain sizes of about 10.3 and 18.5 nm, respectively, precipitates in the amorphous matrix. The crystallized phases are γ-（Fe, Ni） solid solution, Fe2Si, Ni2Si, and Fe3B after annealing at 765 K. The （Ni0.75Fe0.25）73NbsSi10 B12 amorphous alloy was annealed at 720, 750, and 800 K; and the crystallization phases, γ（Fe, Ni） solid solution, （Fe, Ni）23B6. Ni31Si12 and Nb2NiB0.16 form simultaneously.     

The thermodynamic properties of calcium intermetallic compounds

The thermodynamic properties of calcium alloys have been measured by emf (an original pin-point method) and calorimetry in recent years. A review of experimental results obtained for 15 binary (Ca,M) systems is presented (with M Ni, Pd, Pt, Cu, Ag, Au, Mg, Al, Ga, Si, Ge, Sn, Pb, Sb, Bi), and numerical optimization is performed for some of them. Application to the ternary (Ca,Sn,Pb) system of industrial interest, allowed calculation of the phase diagram for x(Ca) 0.25.     

New modelling of the B2 phase and its associated martensitic transformation in the Ti–Ni system

A symmetric two-sublattice model (Ni, Ti, Va)_0.5(Ni, Ti, Va)_0.5 is applied to describe the intermediate B2 compound in order to cope with the order–disorder transition in the Ti–Ni system. Using this model, the ordered B2 and the disordered Ti-rich b.c.c. are described by a single Gibbs free energy function. The B2 phase is the parent phase of the martensitic transformation in the TiNi shape memory alloys (SMAs), and its thermodynamic properties are then reassessed with emphasis on its composition range that is critical for SMAs. The low temperature B19′ phase is also evaluated on the basis of the selected experimental data from the martensitic transformation. Properties related to the transformation are studied in comparison with experimental data. The magnetic contribution is examined for the martensitic transformation. All calculations are in satisfactory agreement with experimental phenomena.     

Thermodynamic analysis and assessment of the Ce–Ni system

An optimised set of thermodynamic parameters for the Ce–Ni system has been obtained using the CALPHAD approach. A thorough thermodynamic analysis of the system has been carried out using different calorimetric techniques and the data have been used in the assessment. The free energy of the liquid phase has been described as a function of temperature and composition using a Redlich–Kister polynomial. Solid compounds have been considered as stoichiometric with the exception of the Laves phases. The phase diagram and thermodynamic quantities calculated from assessed parameters agree well with experimental data.     

Experimental determination and Re—optimization of Ni—Ta binary system

1　ＩＮＴＲＯＤＵＣＴＩＯＮＮｉ Ｔａｂｉｎａｒｙａｌｌｏｙｈａｓｂｅｅｎｔｈｅｓｕｂｊｅｃｔｏｆｍｕｃｈｒｅｓｅａｒｃｈｏｗｉｎｇｔｏａｃｏｍｂｉｎａｔｉｏｎｏｆｓｃｉｅｎｔｉｆｉｃａｎｄｔｅｃｈ ｎｏｌｏｇｉｃａｌｉｎｔｅｒｅｓｔ .Ｏｎｏｎｅｈａｎｄ ,ｔ     

Assessment of Co-Cr-Ni ternary system by CALPHAD technique

The Co-Cr-Ni ternary system was critically assessed using the CALPHAD technique.The solution phases including the liquid,γ(Co,Ni),εCo and αCr phases were described by a substitutional solution model.The σ phase was characterized by a three-sublattice model of (Co,Ni)8Cr4(Co,Cr,Ni)18 in order to reproduce its homogeneity range determined by experiments.A self-consistent set of thermodynamic parameters for each phase was derived.