EQUILIBRIUM PHASE DIAGRAMS IN SYSTEM CuO-PbO-Ag

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Boundary slope interrelation method for determination of tie lines in ternary isothermal sections

A new method for interpolation of tie lines in ternary isothermal sections has been developed. This method and a previously reported method have been analyzed for a ternary isothermal section of the Al-Mg-Zn system. The technique is well suited for use in computer-based phase diagram storage and retrieval systems. An application of the present interpolation method for equilibrium crystallization path determination is discussed.     

Structural materials: metal–silicon–boron: On the melting behavior of Mo–Si–B alloys

Phase relations in the entire ternary system Mo–Si–B were studied at subsolidus temperatures on alloys prepared by arc-melting and employing Pirani–Althertum melting point data, differential thermal analysis, light and electron microscopy, X-ray diffraction, and electron probe microanalysis including the light element boron. All isothermal reaction temperatures measured were used to construct two vertical sections and a Schulz–Scheil flow diagram monitoring solidification (crystallization) in thermodynamic equilibrium over the whole concentration range. The ternary compound Mo₅SiB₂ exhibits a solubility range from 8 to 13 at.% Si at solidus temperatures. Stoichiometric Mo₅SiB₂ forms from a pseudobinary peritectic reaction with a maximum tie line at 2130 °C. The phase diagram is presented as a melting diagram projection.     

Subsolidus phase relations in the ZnO–MoO3–B2O3, ZnO–MoO3–WO3 and ZnO–WO3–B2O3 ternary systems

The subsolidus phase relations in the ZnO–MoO₃–B₂O₃, ZnO–MoO₃–WO₃ and ZnO–WO₃–B₂O₃ ternary systems have been investigated by the means of X-ray powder diffraction (XRD). There is no ternary compound in all the systems. There are five binary compounds and five tie lines in the ZnO–MoO₃–B₂O₃ system. This system can be divided into six 3-phase regions. There are three binary compounds and three tie lines in the ZnO–MoO₃–WO₃ system. This system can be divided into four 3-phase regions. There are four binary compounds and four tie lines in the ZnO–WO₃–B₂O₃ system. This system can be divided into five 3-phase regions. The possible component regions for ZnO single crystal flux growth were discussed. The phase diagram of Zn₃B₂O₆–ZnWO₄ pseudo-binary system has been constructed, and the result reveals this system is eutectic system. The eutectic temperature is 1007 °C and eutectic point component is 70 mol% Zn₃B₂O₆.     

Correlation between Fluidity and Solidification—Microstructures at the Aluminium-rich Corner of the Al-Cu-Si System

Abstract

Systematic investigations were carried out to study fluidity length, obtained in a linear testpiece, as a function of Cu and Si concentration at the aluminium-rich corner of the Al-Cu-Si system. The results obtained, combined with subsequent microstructural evaluation, has suggested that fluidity length is in balance between the latent heat of fusion of the proeutectic phases, the fluidity length of the binary and ternary eutectics present in each alloy, and the amount of proeutectic phases according to the tie lines of the equilibrium diagram.     

Experimental Investigation of Phase Equilibria in the Co-Cr-Nb System at 1000, 1100, and 1200 °C

Phase equilibria in the Co-Cr-Nb ternary system were experimentally investigated by using back-scattered scanning electron microscopy, electron probe microanalysis, composition mapping and x-ray diffraction on equilibrated alloys. In this study, isothermal sections of the Co-Cr-Nb ternary system at 1000, 1100 and 1200 °C were determined. The intermetallic compounds Co₇Nb₆ and CoCrNb, together with their single phase regions were determined on all three isotherms, as well as three tie triangles involving the (Nb) + Co₇Nb₆ + CoCrNb, (αCr) + σ + CoCrNb and (αCo) + σ + CoCrNb phases. The current diagrams differed significantly from a previous isotherm reported at 1000 °C. The newly determined phase equilibria in the Co-Cr-Nb system may provide useful information for perpendicular magnetic recording materials and high-temperature alloys.     

TerQuat: Approximate prediction of ternary and quaternary phase diagrams comprising stoichiometric phases

The TerQuat method is an easy-to-use tool for a first prediction of ternary and quaternary phase diagrams. A number of simplifications (only stoichiometric compounds; Δ_fG° can be approximated by the Miedema model, ΔH_Miedema, data) allows the user to get an impression of a ternary or quaternary system with only a minimum of knowledge about the system, namely a list of existing compounds. Stable tie lines are calculated by comparison of the Gibbs energy of reaction of all possible reactions between four phases in the ternary. In the quaternary system, all the competing two- and three-phase equilibria are compared with each other, and a list of stable equilibria is generated. In addition, the intersections of stable two- and three-phase equilibria with a user specified plane in the tetrahedron can be calculated and plotted. This enables a simple generation of a space model for the visualization of the quaternary system. This paper was presented at the International Phase Diagram Prediction Symposium sponsored by the ASM/MSD Thermodynamics and Phase Equilibria Committee at Materials Week, October 21-23,1991, in Cincinnati, Ohio. The symposium was organized by John Morral, University of Connecticut, and Philip Nash, Illinois Institute of Technology.     

Determination of isothermal section of Fe-Ti-Zr ternary system at 1173 K

Phase relations in the Fe-Ti-Zr ternary system at 1173 K were investigated by means of diffusion-triple approach together with electron probe microanalysis（EPMA） technique. A series of tie lines and tie-triangles were determined and the isothermal section at 1 173 K was established, which consists of four three-phase fields： β（Ti, Zr）＋FeZr2＋FeTi, FeZr2＋FeTi＋Fe2Zr, FeTi ＋Fe2Zr ＋Fe2Ti and Fe2Zr ＋Fe2Ti ＋Fe. The results show that the largest solubility of Ti in Fe2Zr is about 11.3 %（mole fraction） and the solid solubility of Ti in FeZr2 is about 26.9%, the solid solubility of Zr in Fe2Ti is about 8.1% and the solid solubility of Zr in FeTi is 7.2%. The binary compound FeZr2 is nearly a linear compound. No ternary compound is found.     

多节刚性拉杆制造工艺研究

研究了DNV多节刚性拉杆的生产工艺流程及其实施过程、质量控制方法和热处理工艺.结果表明,采用880℃正火+840～850℃油淬火+540℃和520℃二次回火的热处理工艺,可使多节刚性拉杆获得最佳性能,且该热处理工艺的效率高,生产成本低.     

HXD2机车转向架拉杆座角焊缝疲劳失效机理

针对HXD2型电力机车在某穿越秦岭山脉线路服役中多台次拉杆座角焊缝出现裂纹的问题,进行了试验与仿真分析。发现裂纹表面有明显疲劳辉纹,表明角焊缝服役中发生疲劳失效;焊缝根部是疲劳起裂位置,有多源起裂形貌特征;起裂后裂纹从中心向两侧扩展、从根部向焊缝表面扩展,在接头横截面上裂纹路径与水平方向夹角近似为45°;统计分析和仿真计算表明,角焊缝裂纹的发生与拉杆座/基板之间的间隙值有关联性,根部间隙越大,则角焊缝抗疲劳性能越差;分析其主要机理是间隙较小时,焊缝受压后拉杆座底面与构架基板表面更容易发生接触,接触后基板表面分担部分载荷。因此,间隙较小时,焊缝应力幅较小;而间隙较大时,不仅应力幅较大,而且在焊根处易出现末端尖劈形貌。 创新点： 分析了某穿越秦岭山脉线路HXD2电力机车拉杆座角焊缝疲劳失效行为,揭示了电力机车车架角焊缝疲劳裂纹与角焊缝根部间隙的相关性,阐明了根部间隙影响拉杆座角焊缝抗疲劳性能的机理。     

Thermodynamic investigation of Fe-Ti-Y ternary system

An extensive investigation on the Fe-Ti-Y system was performed via experimental measurement and thermodynamic calculation. The Fe-Ti-Y ternary couples at 1 273 K were prepared with a desire to provide accurate phase relationships needed for the refinement of this ternary phase diagram. And a tentative isothermal section of Fe-Ti-Y at 1 273 K was built based on the experimental information. In the thermodynamic modeling, the thermodynamic parameters for the Ti-Y binary system and the ternary phase in the Fe-Ti-Y system were evaluated. Those for the Fe-Ti and Fe-Y systems from literature were slightly modified for the compatibility. The isothermal sections of Fe-Ti-Y ternary system at 873 K and 1 273 K were calculated. The ternary compound Fe11TiY and Fe2(Ti, Y) solid solution formed from Fe2Ti and Fe2Y are detected, which is in good agreement with the literature information.     

Experimental Investigation of Phase Equilibria in the Fe-Si-Ti Ternary System

The phase equilibria of the Fe-Si-Ti ternary system were investigated by electron probe microanalyzer (EPMA), back scattered electron (BSE) and X-ray diffraction (XRD) on the equilibrated alloys. Twenty-four alloys of the Fe-Si-Ti ternary system were prepared. In this study, three isothermal sections of the Fe-Si-Ti ternary system at 1000, 1100 and 1200 °C were respectively determined and seven ternary compounds were confirmed. The ηFe₅Si₃ phase is discovered at 1100 and disappeared at 1200 °C. The obtained experimental results show that there is large solubilities of Si in the TiFe₂ phase. The newly determined phase equilibria of the Fe-Si-Ti system will provide useful information for the development of silicon steels.     

Experimental Investigation and Thermodynamic Calculation of Phase Equilibria in the Mg-Pb-Sn Ternary System

The phase equilibria of the Mg-Pb-Sn ternary system were investigated using a combined method of electron probe microanalyzer and x-ray diffraction. Three isothermal sections of the Mg-Pb-Sn ternary system at 200, 300 and 400 °C were experimentally established. The phase equilibria of Mg-Pb-Sn ternary system were thermodynamically assessed by using CALPHAD (Calculation of Phase Diagrams) method on the basis of the presently determined experimental data. A consistent set of thermodynamic parameters has been derived for describing the Gibbs free energies of each solution phase and intermetallic compound in the Mg-Pb-Sn ternary system. The calculated phase diagrams and thermodynamic properties in the Mg-Pb-Sn ternary system are in good agreement with experimental data.     

Experimental Determination of Phase Equilibria in the Co-Cr-V Ternary System

The phase equilibria in the Co-Cr-V ternary system were investigated by means of optical microscopy, electron probe microanalysis and x-ray diffraction. Four isothermal sections of the Co-Cr-V ternary system at 800, 1000, 1100 and 1200?°C were established. The experimental results show that: (1) no ternary compound was found in this system; (2) the ?? and (V, Cr) phases form the continuous solid solutions from the Co-Cr side to Co-V side in the isothermal sections at 800-1200?°C.     

The ternary Gd-Li-Mg system: Phase diagram study and computational evaluation

The binary Gd-Li and the ternary Gd-Li-Mg systems were studied experimentally by thermal analysis and phase equilibration and also by thermodynamic calculations using the CALPHAD method. Ternary phase equilibria at 250 °C were studied with 55 different alloys that were annealed for 400 h and analyzed by x-ray diffractometry. A thermodynamic assessment of the binary Gd-Li system was also performed and the calculated phase diagram is presented. In the Gd-Li-Mg system, ternary solubilities of Li in GdMg (up to 5 at.% Li), GdMg₂ (up to approximately 3 at.% Li), and GdMg₃ (up to 5 at.% Li) were found at 250 °C. No ternary compound was observed. Lattice parameters for different compositions are given for these phases. Thermal analysis using a ternary key sample of composition near the invariant reaction L′=L+(βGd)+GdMg provided the data that were needed to determine a thermodynamic parameter for the ternary liquid. Thermodynamic data sets for the ternary solid solution phases were also developed. Based on the present data sets and those of the binary Gd-Mg and Li-Mg systems from the literature, the phase equilibria in the entire ternary system were calculated. Isothermal and vertical sections of the phase diagram and the projection of the liquidus surface are shown. These calculated phase diagrams are well supported by the experimental data.     

The ternary Gd-Li-Mg system: Phase diagram study and computational evaluation

The binary Gd-Li and the ternary Gd-Li-Mg systems were studied experimentally by thermal analysis and phase equilibration and also by thermodynamic calculations using the CALPHAD method. Ternary phase equilibria at 250 °C were studied with 55 different alloys that were annealed for 400 h and analyzed by x-ray diffractometry. A thermodynamic assessment of the binary Gd-Li system was also performed and the calculated phase diagram is presented. In the Gd-Li-Mg system, ternary solubilities of Li in GdMg (up to 5 at.% Li), GdMg₂ (up to approximately 3 at.% Li), and GdMg₃ (up to 5 at.% Li) were found at 250 °C. No ternary compound was observed. Lattice parameters for different compositions are given for these phases. Thermal analysis using a ternary key sample of composition near the invariant reaction L′=L+(βGd)+GdMg provided the data that were needed to determine a thermodynamic parameter for the ternary liquid. Thermodynamic data sets for the ternary solid solution phases were also developed. Based on the present data sets and those of the binary Gd-Mg and Li-Mg systems from the literature, the phase equilibria in the entire ternary system were calculated. Isothermal and vertical sections of the phase diagram and the projection of the liquidus surface are shown. These calculated phase diagrams are well supported by the experimental data.     

Phase equilibria in the Al–Si–V system: The vanadium rich part

The V-rich part of the Al–Si–V phase diagram was determined by a combination of optical microscopy, powder X-ray diffraction (XRD), differential thermal analysis (DTA) and electron probe microanalysis (EPMA). Phase equilibria were investigated at two isothermal sections at 850 and 1300 °C. High temperature DTA was performed to identify the ternary invariant reactions yielding a ternary reaction scheme and the vertical section at 50 at.% V. As cast samples were investigated in order to gain additional information about primary crystallization fields. A liquidus surface projection was constructed for the entire ternary system by combining our experimental data with those from literature.     

Determination of isothermal sections of the Co-Nb-Ni and Ni-Mo-Re ternary systems

The isothermal sections of the Co-Nb-Ni ternary system at 1373 K and the Ni-Mo-Re ternary system at 1473 K were determined by means of diffusion triple and electron probe microanalysis (EPMA).The results indicate that there are three three-phase regions found in the Co-Nb-Ni ternary system at 1373 K:(Ni,Co) NbCo3 Ni3Nb,NbCo3 NbCo2 Ni3Nb,and NbCo2 μ Ni3Nb;and four three-phase regions found in the Ni-Mo-Re ternary system at 1473 K:Re Ni χ,Ni NiMo σ,σ χ Ni,and σ Mo NiMo.No ternary eompoond is observed in the two isothermal sections.The isothermal sections arc contrasted with the previous study.     

基于Miedema模型和Toop模型的Al-Si-Er合金热力学参数计算

运用Miedema混合焓模型计算了Al-Er、Si-Er和Al-Si二元合金的部分热力学性质,选择Er为非对称性组元,在此基础上结合Toop模型计算出Al-Si-Er三元合金的混合焓、过剩熵与过剩自由能。结果表明,Al-Si-Er三元合金的混合焓、过剩熵与过剩自由能在整个浓度范围内均为负值,在富Er和贫Er区域各热力学参数变化趋势较大。通过计算Al、Si和Er 3种组元的偏摩尔过剩自由能得到Al-Si-Er三元合金各组元的等活度值曲线。曲线显示各组元随着摩尔分数的减少其活度值都急剧减小,在三元系成分三角形的中心部分Al、Si和Er的活度值都很小,这表明Al、Si和Er 3种组元之间存在很强的相互作用,易形成三元金属间化合物,这一结论与Al-Si-Er三元相图的实际情况相符合。