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Calculation of the self-formation driving force for composite microstructure in liquid immiscible alloy system

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Progress in Natural Science:Materials International 2005年第2期15卷 74-78页

作者： ikuo ohnuma,Ryosuke KAINUMA,Kiyohito ISHIDA Tohoku University Sendai 980-8579 Japan Department of Materials Science Tohoku University Sendai 980-8579 Japan Department of Materials Science Tohoku University Sendai 980-8579 Japan Department of Materials Science

Using Becker's method, we calculate the interfacial energy between two liquid phases in an immiscible system. Based on the Gibbs-Thomson equation, the force acting on the droplet towards the thermal center can be obtained by integrating the interfacial energy between the droplet and matrix liquid phase, which is related to both the radius of a droplet and the temperature gradient. In addition, the forces of gravitation and buoyancy also act on the droplet. The calculated results indicate that the resultant for these forces together mainly decides the microstructure morphology of the solidified alloy. The calculated results are in good agreement with the corresponding experimental results.

关键词： liquid immiscible alloy system interfacial energy composite materials phase diagram

Development of materials design tool and its application in Pb-free micro-solders in electronic package

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Science China(Technological Sciences) 2010年第6期53卷 1495-1500页

作者： ohnuma ikuo KAINUMA Ryosuke ISHIDA Kiyohito CHANG Austin Y. Department of Materials Science Graduate School of EngineeringTohoku UniversitySendai 980-8579Japan Department of Materials Science and Engineering University of WisconsinMadisonUSA

A materials design tool for developing Pb-free soldering alloys in electronic package was developed based on comprehensive experimental data of phase equilibria and thermodynamic properties data accumulated with the CALPHAD (calculation of phase diagrams) method and contains 10 elements,namely,Ag,Au,Bi,Cu,In,Ni,Sb,Sn,Zn and *** can handle the calculation of phase diagrams in all combinations of these elements and all composition *** addition,based on this tool,the liquidus,solidus,phase fractions and constitutions,equilibrium and non-equilibrium solidification behavior,surface tension and viscosity of liquid,diffusion reactions and microstructural evolution,*** be *** examples of the calculation and application of this tool are *** design tool is expected to be a powerful tool for the development of Pb-free solders,as well as for promoting the understanding of the interfacial phenomena between Cu substrate and Pb-free solders in electronic packaging technology.

关键词： Pb-free solders thermodynamic database calculation of phase diagram phase field method interfacial reaction

Thermodynamic assessment of the Ni-Sb binary system

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Rare Metals 2008年第4期27卷 384-392页

作者： CAO Zhanmin TAKAKU Yoshikazu ohnuma ikuo KAINUMA Ryosuke ZHU Hongmin ISHIDA Kiyohito School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Department of Materials Science Graduate School of Engineering Tohoku University Sendal 980-8578 Japan

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.

关键词： Ni-Sb binary system thermodynamic assessment CALPHAD phase diagram

Thermodynamic reassessment of Ni–Ga binary system

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Rare Metals 2015年第12期34卷 864-872页

作者： Zhan-Min Cao Xian Shi Wei Xie ikuo ohnuma Kiyohito Ishida Zhi-Yu Qiao State Key Laboratory of Advanced Metallurgy School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Department of Materials Science Graduate School of Engineering Tohoku University

New experimental measurements of the phase diagram and the mixing enthalpy of liquid phase along with the previous experimental data were used in a reassessment of the Ni–Ga system. A set of self-consistent thermodynamic parameters of the Ni–Ga system is obtained using the calculation of phase diagram (CALPHAD) technique, and the available phase diagram and thermodynamic data are reproduced well within experimental error limits. Some noticeable improvements are obtained in the present work compared with the previous assessment: (1) the calculated Ga-rich liquidus is more reasonable; (2) Ni3Ga7 is adopted as the most Ga-rich compound rather than NiGa4; (3) the Ni5Ga3 phase is treated as the nonstoichiometric compound with consideration of its narrow homogeneity range; (4) the phase transformation between B81.5_Ni3Ga2 and Ni13Ga9 is considered instead of treating them as Ni3Ga2 phase simply; (5) the latest experimental data of mixing enthalpy for the liquid phase are adopted. The present study can be used as a basis for the development of a thermodynamic database of the Ni-based semiconductor alloy systems.

关键词： Ni–Ga system CALPHAD technique Thermodynamic reassessment Phase diagram

Design of Pb-free solders in electronic packaging by computational thermodynamics and kinetics

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材料与冶金学报 2005年第2期4卷 122-125页

作者：刘兴军 ohnuma ikuo KAINUMA Ryosuke ISHIDA Kiyohito 厦门大学 Department of Materials Science Graduate School of Engineering Tohoku University Sendai 980-8579 Japan

Computational thermodynamics and kinetics were used to design the Pb-free micro-solders for replacing the conventional Sn-Pb solders because of the health and environmental safety problem. On the basis of CALPHAD (Calculation of Phase Diagrams) method we can easily calculate properties such as the liquidus projection, isothermal and vertical sectional diagrams and phase fraction in multi-component system including Ag, Bi, Cu, In, Sb, Sn, Zn and Pb elements. In addition, other related information such as the surface tension, viscosity of the liquid phase and solidification simulation can also be obtained. DICTRA (Diffusion Controlled Transformation) software was used to simulate the interfacial reactions between substrate and Pb-free solders, which can easily give the information on the growth of intermetallic compounds and moving speed of interface between substrate and solders etc.

关键词：电子组装无铅焊料热力学动力学合金设计

Design and development of the self-assemble Cu-Fe base composites

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材料与冶金学报 2005年第2期4卷 127-131页

作者：王翠萍 ohnuma ikuo KAINUMA Ryosuke ISHIDA Kiyohito 厦门大学 Department of Materials Science Graduate School of Engineering Tohoku University Sendai 980-8579 Japan

The Cu-Fe base alloys with liquid immiscible were prepared by gas atomization technique and conventional solidification process, the self-assemble composite microstructures in powders and bulk materials can be obtained under gravity conditions, respectively, and the minor liquid phase always forms the center of composite microstructure. It is shown that the formation of the core-type macroscopic morphology is strongly connected with the existence of a stable miscibility gap of the liquid phase in the Cu-Fe base alloys. This result can be explained by a mechanism that the minor droplets as the second phase are forced to move into the thermal center due to Marangoni motion, which is caused by the temperature dependence of interfacial energy between two liquid phases.

关键词：自组装Cu-Fe基复合材料相图液态互溶区性能

Miscibility gap and stability of B2 phase in the Co-Al based ternary systems

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材料与冶金学报 2005年第2期4卷 121-121页

作者：贝沼亮介 KOBAYASHI Kosei ohnuma ikuo ISHIDA Kiyohito 日本东北大学 Department of Materials Science Graduate School of Engineering Tohoku UniversityAoba-yama 02 Sendai 980-8579 Japan Department of Materials Science

Information on phase equilibria in the Co-Al based systems which are related to some magnetic and heat resistance materials is important for their microstructural control. Recently, it was proposed with a theoretical calculation on electronic band structure that some Heusler-type alloys Co2XAl （X: Cr and Mn） should be a new type of spinelectronic materials so-called half-metallic ferromagnet. In the case of the Co2CrAl, however, magnetic properties expected from the theoretical work can not been experimentally obtained and the reason has been still unknown. On the other hand, a tunneling magnetoresistance （TMR） effect due to the half-metallic properties was reported in Co2（Cr0.6 Fe0.4 ）Al alloy, but not the Co2CrAl *** the present paper, it is reported that this discrepancy with the theoretical work in the Co2CrAl alloy is bought about by phase separation between A2 and B2 phases, and that the substitution of Fe for Cr can suppress the precipitation of A2 phase in the B2 phase. Such a phase separation is originally due to the miscibility gap between CoAl and Cr formed in the Co-Al-Cr ternary system as well as that reported by Hao et al. in the Ni-Co-Al-Fe system.

关键词： Co-A1基三元系 B2相溶解度间隙稳定性

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多元系B2相的热力学描述

材料与冶金学报 2005年第2期4卷 148-151页

作者：蒋敏大沼郁雄贝沼亮介石田清仁日本东北大学工学部工学研究科仙台9808579

B2相广泛存在于铁基、钴基和镍基合金中.B2相的析出对于合金组织和性能具有重要影响.本文指出了合理描述B2相的热力学模型,并就如何简单有效地描述多元合金系中的B2相,以及如何处理在此过程中可能出现的各种问题,进行了深入的探讨和研究.

关键词：多元系 B2相热力学

Effect of the interaction between the chemical and the magnetic ordering on the phase equilibria of iron base alloys

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材料与冶金学报 2005年第2期4卷 110-110页

作者：大沼郁雄 KAINUMA Ryosuke ISHIDA Kiyohito 日本东北大学 Department of Metallurgy Graduate School of Engineering Tohoku UniversityAoba-yama 6-6-02 Sendai 980-8579 Japan Department of Metallurgy

It is well known that the magnetic properties such as the Curie temperature Tmag C and the mean magnetic moment β of ordered compounds have different values from those of the disordered solutions. For instance, both Tmag c and β of the Ni3Pt （L12） and NiPt （L10） and Tmag c of the CoPt （L10） and CoPt3 （L12） ordered compounds are strongly depressed due to the ordering compared with those of the metastable disordered Ni-Pt and Co-Pt alloys. On the other hand, the γ’-FeNi3 （L12） and the α’-FeCo （B2） ordered compounds have higher Tmag c and β values comparing with the disordered solution phases, γ （A1） and α （A2）, respectively. In consequence, the stability of the ordered phase is depressed or enhanced due to the interaction between the chemical and magnetic ordering caused by the decrease or increase of Tmag c and β values. The purpose of this study is to investigate the effect of the interaction between the chemical and the magnetic ordering on the phase equilibria in the Fe-X（X=Al, Co, Ni, Rh, Si） binary *** Gibbs energy of the α（A2）, γ（A1） and liquid phases is described by a sub-regular solution approximation. The ordering contribution to the Gibbs energy ,ΔGorder m, and deviations of magnetic properties, ΔTmag c and Δβ, of the ordered compounds, FeAl （B2）, Fe3Al （D03）, FeCo （B2）, FeRh （B2）, FeSi （B2）, Fe3Si （D03） and FeNi3 （L12） is introduced by the split compound energy formalism. Effect of the interaction between the chemical ordering, B2, D03 and L12 and the magnetic ordering on the phase equilibria will be discussed according to the calculated phase diagrams of the Fe-X binary systems.

关键词：化学有序磁有序铁基合金相平衡交互作用