Thermodynamic Modeling of the Al-Ti-V Ternary System

The sub-binary systems Al-Ti, Ti-V, and Al-V are reviewed and adopted from the previous assessments, the thermodynamic analysis of the Al-Ti-V ternary system is performed by the CALPHAD approach, and a set of self-consistent thermodynamic parameters of the ternary system are obtained. Furthermore, the isothermal sections of this system at 1073 K, 1173 K, 1273 K, 1373 K, and 1473 K (800 °C, 900 °C, 1000 °C, 1100 °C, and 1200 °C) and the ternary invariant equilibria are calculated and compared with the corresponding experimental data, and all are in good agreement with most of the experimental results. Thus, the optimized thermodynamic parameters in this study may provide more accurate guidance to develop the new alloys involving it.     

Optimizing the Diffusion Welding Process for Alloy 800H: Thermodynamic,Diffusion Modeling,and Experimental Work

A research effort was made to evaluate the usefulness of modern thermodynamic and diffusion computational tools, Thermo-Calc and Dictra (Thermo_Calc Software, Inc., McMurray, PA), in optimizing the parameters for diffusion welding of Alloy 800H. This would achieve a substantial reduction in the overall number of experiments required to achieve optimal welding and post-weld heat treatment conditions. This problem is important because diffusion-welded components of Alloy 800H are being evaluated for use in assembling compact, micro-channel heat exchangers that are being proposed in the design of a high-temperature, gas-cooled reactor by the U.S. Department of Energy. The modeling was done in close contact with experimental work. The latter included using the Gleeble 3500 System (Dynamic Systems, Inc., Poestenkill, NY) for welding simulation, mechanical property measurement, and light optical and scanning electron microscopy. The modeling efforts suggested a temperature of 1423 K (1150 °C) for 1 hour with an applied pressure of 5 MPa using a 15-μm Ni foil as joint filler to reduce chromium oxidation on the welded surfaces. Good agreement between modeled and experimentally determined concentration gradients was achieved, and model refinements to account for the complexity of actual alloy materials are suggested.     

Experimental Investigation and Thermodynamic Modeling of the Ag-Cu-Ge System

Metallurgical and Materials Transactions A - The liquidus surface projection was re-investigated using scanning electron microscopy with energy dispersive spectrometer and differential thermal...     

Experimental Investigation and Thermodynamic Modeling for the Mg-Nd-Sr System

Microstructure examination, phase analysis, and DSC measurement on the equilibrated ternary alloys not only enabled exploration of the phase equilibria relations of the Mg-Nd-Sr ternary but also thermodynamic assessment of the ternary system in the context of the CALPHAD approach. Thermodynamic modeling, further coupled with first principle calculations, was thereafter used to predict a panoramic phase diagram for the Mg-Nd-Sr ternary system at the Mg-rich corner.     

Ni-Sb二元合金的相关系与热力学性质的研究

利用非等温等蒸气压法研究了Ni-Sb二元合金的相关系，确定了Ni5Sb2和γ-NiSb的相边界。当温度高于715℃时Ni-Sb体系中不存在Ni3Sb相，只有Ni5Sb2相存在，Ni5Sb2的相边界是(原子分数)29．42％～31．6％Sb，γ-NiSb的相边界为(原子分数)50．2％～52．58％Sb。测定了非化学计量金属间化合物Ni5sb2和γ-NiSb非化学计量范围内Sb的活度，并计算了Sb的偏摩尔焓和偏摩尔熵等热力学性质。     

Gibbs Energy Modeling of the Cu-S Liquid Phase: Completion of the Thermodynamic Calculation of the Cu-S System

Metallurgical and Materials Transactions B - A thorough review and critical evaluation of all experimental sulfur potential and phase diagram data available from the literature has been made for...     

Understanding of Void Formation in Cu/Sn-Sn/Cu System During Transient Liquid Phase Bonding Process Through Diffusion Modeling

Metallurgical and Materials Transactions B - Transient Liquid Phase (TPL) bounding of Sn foil sandwiched between two Cu foils involves, in the temperature range above the melting point of Sn...     

Innovation Diffusion Modeling in the Construction Industry

The innovation diffusion modeling approach proposes that the diffusion of an innovation in an industry is mainly driven by internal and external influence factors. But the innovation diffusion models used in previous research studies conducted in the construction management literature are excessively restrictive. This research uses a more flexible model called the nonuniform influence (NUI) model to study the diffusion of a technological innovation, namely, computer aided design (CAD) technology in the Turkish architectural design practice; and an administrative innovation, namely, ISO 9000 certification in the Turkish precast concrete industry. The research findings point out that the NUI model performs significantly better than previously used models and that internal rather than external influence plays a predominant role in the diffusion of both types of innovation. The research findings provide additional insights into the diffusion of CAD technology and ISO 9000 certification which could not be captured by the previously used diffusion models. They show that internal influence on the diffusion of CAD technology increases with passage of time and that internal influence on the diffusion ISO 9000 certification decreases with passage of time. The research has academic importance because it addresses the limitations of previous innovation diffusion research and provides quantitative insights into the diffusion of innovations; knowledge that is lacking in the construction management literature. The research is of practical importance because it provides useful observations that architecture/engineering/construction firms can use to understand the presence of imitative behavior in the innovation diffusion process and the role of innovation characteristics in imitative behavior.     

热轧低碳钢不同冷却模式下的相变模拟与验证

利用计算机模拟技术，研究了控轧控冷中输出辊道上冷却模式对低碳钢相变的影响。以低碳钢SS400为例，针对鞍钢热轧带钢厂1780生产线，计算了输出辊道上3种不同冷却模式下低碳钢的相变行为，包括铁素体转变开始温度、组成相体积分数随时间的变化以及铁素体体积分数沿带钢长度方向的分布。研究表明，冷却模式对输出辊道上带钢的温度一时间曲线、铁素体转变开始温度及组成相的演化过程影响较大，但对最终组成相的体积分数影响较小。     

热力学模拟计算软件FactSage及其应用

介绍了当今最具代表性的Thermo-Calc和FactSage热力学计算软件. 将FactSage应用于金川镍闪速熔炼过程的复杂多元多相平衡计算, 表明金川镍闪速熔炼炉渣中铜含量的理论计算值(0.043%～0.060%)远小于实际值(0.28%～0.30%), 进一步降低渣中含铜量热力学上是可能的;利用FactSage计算了一系列不同成分的Fe-B合金在实际应用条件下的相组成和相含量及其变化规律, 综合考虑各合金的工艺性能、力学性能和耐锌液腐蚀性能, 用优选方案制备的成分为7.01%B, 5.05%B和3.31%B, 相组成为α-Fe Fe2B的Fe-B二元合金可较好地满足抗液锌腐蚀结构材料的综合性能要求.     

A Coupled Experimental Study and Thermodynamic Modeling of the SiO2-P2O5 System

A coupled key phase diagram experimental study and thermodynamic modeling of the SiO₂-P₂O₅ system was conducted. Equilibration and quenching experiments using sealed Pt crucibles were performed in the SiO₂-rich region to resolve inconsistencies found in the literature data about the SiO₂ liquidus. Based on new experimental data and all available and reliable phase diagram and thermodynamic data, the thermodynamic optimization of the SiO₂-P₂O₅ system was carried out to obtain a set of thermodynamic equations for liquid and solid phases in the system. The liquidus slope of SiO₂ indicates that P₂O₅ in the SiO₂-rich liquid exists mainly in the form of P₂O₇ ^4? instead of PO₄ ^3?. Thermodynamic properties of the liquid solution can be predicted from the Gibbs energy of the liquid phase.     

Experimental Investigation and Thermodynamic Calculations of the Bi-Ge-Sb Phase Diagram

A phase diagram of the Bi-Ge-Sb ternary system was investigated experimentally by differential thermal analysis (DTA), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and X-ray powder diffraction (XRD) methods and theoretically by the CALPHAD method. The liquidus projection; invariant equilibria; and three vertical sections, Sb-Bi_0.5Ge_0.5, Ge-Bi_0.5Sb_0.5, and Bi-Ge_0.5Sb_0.5, as well as isothermal sections at 773 K and 373 K (500 °C and 100 °C), were predicted using optimized thermodynamic parameters for constitutive binary systems from the literature. In addition, phase transition temperatures of the selected samples with compositions along calculated isopleths were experimentally determined using DTA. Predicted isothermal sections at 773 K and 373 K (500 °C and 100 °C) were compared with the results of the SEM-EDS and XRD analysis from this work. In both cases, good agreement between the extrapolated phase diagram and experimental results was obtained. Alloys from the three studied vertical sections were additionally analyzed using the Brinell hardness test.     

Thermodynamic Modeling of Arsenic in Copper Smelting Processes

Published data on the activity coefficients of arsenic in liquid copper, matte and, slag have been reviewed, assessed, and used in the development of thermodynamic databases for solution models of melts. The databases were validated against the literature data on the equilibrium distribution of arsenic between the matte and the slag. The models and databases were used in investigating the effects of matte grade, slag chemistry, SO₂ partial pressure, arsenic loading, and temperature on the equilibrium distribution of arsenic between the melts and gas phase during copper smelting and converting. The results obtained show that the continuous smelting processes operates close to equilibrium between condensed phases with most arsenic reporting to the gas phase. A comparison of the batch and continuous converting processes showed a considerable difference with respect to the elimination of the arsenic from condensed phases. These results indicate batch processes to be more efficient in the removal of arsenic through the gas stream.