Fe-Cr-Ni-C四元系奥氏体与碳化物之间的相平衡计算

将Bjorn Uhrenius描述Fe-C基三元合金体系热力学性质的亚点阵模型扩展后应用于Fe-C基四元合金体系,给出了自由能函数关系表达式,并且在Biorn Uhrc-nius对Fe-Cr-C系热力学平衡计算的基础上,再结合Nishizawa对于Cr-Ni二元系给出的交互作用参数,对Fe-Cr-Ni-C系中固溶体和碳化物的两相平衡进行了计算求解。     

常用二元熔盐氯化物相图及其热力学性质的最优化

本文介绍了一种优化处理二元相图及热力学性质的方法。通过系统分析全部所获得的LiCl—KCl,LiCl—SrCl₂,NaCl—SrCl₂,NaCl—CaCl₂,NaCl—BaCl₂,KCl—BaCl₂,CaCl₂—BaCl₂,BaCl₂—SrCl₂等八个二元系热力学性质和相图的数据并进行优化处理,取得了热力学性质和相图自相一致的结果。     

钨矿物原料碱分解的理论与工艺

针对难处理白钨矿的冶炼问题,采用热球磨(机械活化)工艺,成功地实现了高钙黑钨矿乃至白钨矿的氢氧化钠分解并在国内广泛推广应用,这种工艺过去国外专家基于理论分析和工程实践认为是不可能的。针对新技术带来的理论问题,进行了详细的热力学研究,在实验测定的基础上,绘制了(CaO-)Na2O-WO3-H2O系赝三元相图。该赝三元相图不仅对机械活化碱分解白钨矿的工艺给出了合理的热力学解释,同时还说明即便在单纯的高压釜中白钨矿的碱分解过程也有良好的热力学窗口,为碱压煮分解工艺提供了理论基础,使之成为当前钨矿分解的主流工艺。此外,(CaO-)Na2O-WO3-H2O系赝三元相图从理论上还预测了更为普遍的白钨矿常压碱分解的工作窗口,即过程中保持NaOH浓度超过临界值,则甚至不必采用高温压煮的工作条件也能实现白钨矿的分解。研究中考虑到较低温度下高浓度NaOH分解矿浆具有极高黏度的特性,为解决分解过程的传质和动力学传质问题,借鉴了高分子塑料加工领域处理高黏度物料的成功经验,发明了在双螺杆挤出机中,连续分解黑、白钨精矿的"反应挤出法"碱分解工艺。     

局域平衡原理与相图的扩散偶法测定

介绍了局域平衡原理和扩散偶法测定平衡相图的方法要点.扩散偶法是一种高效的、可靠的相图测定方法,它可以大幅度减少实验工作量,减少原材料消耗,加快相图实测进程.此外,这种方法还具有可直接测定相平衡关系、相平衡成分,避免“过冷效应”等优点,特别适合于多组元系统平衡相图的实验测定.     

W、Mo、Al、Ti对GH220合金微量相影响

应用综合分析手段对不同W、Mo、Al、Ti含量的GH220合金相的溶解、析出规律进行了研究。找出了主要合金元素对析出相的影响,进一步揭示了合金中微量相的变化规律,给出了不同热处理工艺下相的含量。为合金的研制和使用提供了重要依据。     

The Reactions of Titanium and Niobium with Phosphorus

The 1070 K isothermal section of the phase diagram in the region of 0-0.67 molar fraction of P has been constructed by x-ray structure analysis in research on component interaction in the Ti ― Nb ― P system. Two series of continuous substitutional solid solutions are formed: (Ti, Nb₃P (Ti₃P) and (Ti, Nb)₇P₄ (Nb₇P₄), both between isostructural phosphides. The solid solutions based on the phosphides TiP (TiAs) and NbP (NbAs) attain the compositions Ti_0.8Nb_0.2P and Nb_0.9Ti_0.1P, while those based on the phosphides Nb₂P (Nb₂P), Ti₂P (Ti₂P), Ti₅P₃ (Yb₅Sb₃) attain the compositions Nb_1.9Ti_0.1P, Ti_1.9Nb_0.1P, Ti_4.6Nb_0.4P₃. Ternary phosphides are not formed in this system. The interactions in the Ti ― (V, Nb) ― P systems are examined.     

Phase diagram of the Al2O3-ZrO2-Er2O3 system. III. Solidus surface and phase equilibria in alloy crystallization

The solidus surface for the Al₂O₃-ZrO₂-Er₂O₃ phase is projected for the first time onto the concentration triangle. It consists of five isothermal three-phase fields that correspond to four invariant eutectic equilibria, one invariant transformation equilibrium, and six ruled binary eutectic solidus surfaces. The highest solidus temperature in the system is 2710 °C, which is the melting point of pure ZrO₂, and the lowest is 1720°C, which is the melting point of the ternary eutectic AL + F + Er₃A₅. Neither ternary phases nor visible solid solution areas based on components and binary compounds are found in the system. Based on the data on bounding binary systems, liquidus, and solidus surfaces, the phase equilibrium diagram and reaction scheme for equilibrium crystallization of Al₂O₃-ZrO₂-Er₂O₃ alloys are constructed. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 5–6 (455), pp. 74–83, 2007.     

空气气氛条件下CaO-Al2O3-CeO2渣系在1500℃的相平衡关系

采用热力学平衡实验,结合SEM-EDS等检测方法,确定了空气气氛条件下CaO-Al₂O₃-CeO₂渣系在1 500℃的相平衡关系,并绘制出该渣系的等温相图.在空气气氛条件下,CaO-Al₂O₃-CeO₂渣系在1 500℃时存在着三种三相平衡(CA+CA₂+CeO₂,L+CaO+CeO₂,L+CA+CeO₂)和两种两相平衡(L+CeO₂,L+CaO),根据各平衡相关系划分了相应相区,且CeO₂在该渣系中的最大溶解度为28%(质量分数).     

Thermodynamics of Liquid Alloys and Metastable Phase Transformations in the Copper - Titanium System

We have used solution calorimetry at temperatures of 1573 K and 1873 K over broad concentration ranges to study the mixing enthalpy of Cu - Ti liquid alloys. The molar mixing enthalpies of the system are significant negative values. We have established the temperature dependence of the molar mixing enthalpies of the system: there is an increase in their exothermicity as the temperature is lowered. The significant negative mixing enthalpies of the system allow us to conclude that the chemical bonds are localized in the studied melts and consequently associates form. We tested this conclusion within ideal associated solution theory, which describes well the results obtained with a set of CuTi and CuTi₂ associates. Using the model obtained, we have calculated the excess thermodynamic functions of mixing (enthalpy, Gibbs free energy, heat capacity) for the liquid alloys. We estimated the Gibbs energies of fcc, bcc, and hcp solutions in the system by the CALPHAD method, using data from the initial sections of the phase diagrams and from the corresponding thermodynamic data. We have calculated the metastable phase equilibria between the limiting solid solutions and the liquid or supercooled liquid phase. It was shown that for the supercooled liquid and the amorphous phase, a broad concentration range of relative thermodynamic stability can be obtained. The concentration range of amorphization of Cu - Ti melts corresponds to the position of the metastable liquidus line and the T₀ line at temperatures close to the temperature range of amorphous solidification. __________ Translated from Poroshkovaya Metallurgiya, Nos. 5–6(443), pp. 67–80, May–June, 2005.     

RH冶炼含P、Ti超低碳钢生产实践

为了解决含P、Ti超低碳钢浇注过程中的絮流问题,提高温度和夹杂物控制水平,分析了钢水中P、Ti对夹杂物的影响,尝试了不同的精炼路线、RH合金化、循环制度和钢水浇注前的静置时间,最终实现了钢水的稳定浇注。     

Reaction of Tungsten with Melts in the Cu - Co System

We have studied the solubility at 1200°C of tungsten in Cu - Co melts and the growth kinetics of a W₆Co₇ layer at the tungsten — melt interface. We have established the composition of the melt in the three-phase equilibrium tungsten — W₆Co₇ — melt: 0.0195 Co, 4.8 · 10⁻⁵ W, the rest is Cu (in atomic fractions). In the studied composition range for the melt, the solubility of tungsten is described well by the expression: lgX_W = −7.117 + 25.7 · X_Co ^1/2 − 41.06 · X_Co, where X_W and X_Co are the atomic fractions of the corresponding elements in the melt. We have determined the correlation between the growth rate for a layer of tungsten-containing phase at the tungsten — melt interface and the thermodynamic characteristics of the melt. __________ Translated from Poroshkovaya Metallurgiya, Nos. 5–6(443), pp. 81–86, May–June, 2005.     

Al-Zn(Cu)合金的相变和Al-Zn-Cu系相图

Al-Zn-Cusystemistheimportantbasisfor practicalAlalloysandZnalloys[1].Amiscibility gapofthefccphaseexistsabove277℃inthe Al Znsystem[2].Thealloywhosecompositionis atthetopofthemiscibilitygapiscalledsym metricalalloyAlZn.Thisalloyhasmanytypical properties.Theimportantoneisthatthespi nodaldecompositioneasilytakesplaceinit.In ordertoavoidthedecomposition,Cuhasbeen added,whichiseffective.Additionof2%Cu molefractioncoulddelaythespinodaldecompo sitionfortwogrades[3,4].AlZn 2Cuisanalloy which…     

作为材料设计基础的相图研究

介绍了现代材料设计与相图研究之间的关系，强调了计算相图的出现使相图研究成为材料的设计的一部分，相图计算程序系统的另一重要功能是评估和优化热力学参数，以双相纳米材料、宽滞后形状记忆合金、钕铁硼永磁合金、钛铝金属间化合物和低温用钢的研究开发为例，说明了相图研究在材料设计上的重要作用。     

Reaction mechanism of phosphorus with multi phase fluxes during hot metal dephosphorization

The formation of solid solution combined with tricalcium phosphate and dicalcium silicate could promote a considerable removal of phosphorus from liquid slag to solid during hot metal dephosphorization,and thus the dephosphorization by using multi phase fluxes could significantly decrease the consumption of lime. However,the reaction mechanism of multi phase fluxes has not been understood clearly.In the present study,the phase diagram for the CaO-SiO₂-FeO-P₂O₅ system has been measured with certain oxygen partial pressure at hot metal pretreatment temperature.Comparing with the CaO-SiO₂-FeO system,shrinkage of liquid phase area at higher FeO contents was observed at 1 673 K with oxygen partial pressure of 9.2×10^-11 atm.     

Reactions of niobium and tungsten with phosphorus

X-ray diffraction methods have been applied to the component interaction in the Nb-W-P system in the region of 0–0.67 molar parts of P. An isothermal section of the phase diagram at 1070 K has been constructed. No ternary compounds are formed in the system. The phosphide Nb₃P (structure of Ti₃P type) dissolves tungsten to the limiting composition N_1.8W_1.2P (a = 1.0006(6) nm, c = 0.5073(2) nm). The solubility of tungsten in other niobium phosphides does not exceed 0.05 molar fraction. __________ Translated from Poroshkovaya Metallurgiya, Nos. 7–8(450), pp. 76–80, July–August, 2006.     

Structure and Properties of Ceramics Based on Tungsten and Titanium Borides and Boron Carbide

The W₂B TiB₂ B₄C ceramics studied were hot-pressed from composite powders synthesized by thermal reduction of boron carbide. The resulting materials have a skeleton structure with a boron carbide binder when the B₄C content is high and an inclusion-matrix structure when the B₄C content is low. The grain size varies from 5 to 20 m, depending on the preparation conditions. The composite has a hardness of 17.5-20 GPa with a strength in the range 500-1000 MPa.     

由稳定化合物熔化焓提取二元系活度

本文从二元系中稳定化合物与液相平衡关系入手,导出了由稳定化合物的熔化焓计算二元系活度的新公式。通过对In-Sb二元系的活度计算验证了本方法的可行性,并用这一新方法预报了半导体Ga-As二元系的活度。     

氢化脱氢法制备钛粉工艺研究

介绍了生产加工钛粉最常用的方法——氢化脱氢法。金属钛（粉）在一定温度下便开始与氢气发生剧烈的反应，当含氢量大于2．3％时，产物疏松，易于粉碎成细小颗粒的氢化钛粉，氢化钛粉经过大约700℃左右的温度，将其分解以及将钛粉中固溶的大部分氢除去，可得到钛粉。从热力学原理、脱氢曲线，差热分析、平衡分压与氢气的关系等方面对氢化脱氢法做了概要的分析。试验证明，钛中氢的含量随温度的升高逐渐降低，在680℃时氢化钛出现吸热峰迅速分解，钛的氢化反应温度区间为350～680℃。氢化脱氢法生产的钛粉的杂质主要取决于原料的纯度和杂质情况，严格注意操作中的环节，只会引入少量的氧或碳等杂质。对于相同原料制取的钛粉，粒度越细，其含氧量越高。