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。     

相图计算及其应用

综述相图计算方法的发展现状、相图热力学计算常用的相描述模型及常用的热力学计算软件,并以Cu–Fe–Mn和Fe–Mn–Ni体系为例重点介绍相图热力学计算在材料设计及制备中的应用。     

第一性原理计算在相图计算中的应用研究进展

相图计算 （Calculation of Phase Diagram, CALPHAD)是冶金 、化工 、材料设计等各个领域的重要研究工具,随着传统材料体系的研究深入和新材料体系的不断被发现,相关的相图和热力学实验数据愈显匮乏.基于电子层面的第一性原理计算（First-principles Calculations),可以从体系基态性质出发,研究亚稳相、金属间化合物的结构、合金的稳定性,促进 CALPHAD 的发展.文中关注了近年来第一性原理计算在 CALPHAD 技术当中的应用研究进展,从计算化合物的能量性质,相图,动力学性质等方面进行系统阐述.      

FeO-V2O5二元相图的研究

对FeOV2O5二元系通过XRD试验进行物相分析,理论计算中间化合物的热力学参数,并建立了溶液热力学模型,结合FACT软件计算绘制出FeO-V2O5二元系相图,通过DSC试验和XRD试验验证相图.此体系相图由三个共晶反应组成并且生成两种中间化合物反式尖晶石Fe2VO4和钒酸铁FeVO4,试验的结果对理论计算出的相图有很...     

基于Thermo--Calc的中锰中铝Fe--Mn--Al--C低密度钢类Schaeffler相图绘制与评估

含铝低密度钢由于其较好的综合力学性能和低密度特征引起结构钢领域研究人员的广泛关注.本文利用ThermoCalc热力学计算软件结合TCFE 7数据库,计算中锰中铝含量Fe-Mn-Al-C钢在不同温度的热力学平衡状态,总结其两相区相比例的变化规律,通过平移和修正等处理方法,绘制针对中锰中铝钢合金成分和相设计的类Schaeffler相图.结合马氏体转变温度的计算讨论对应不同合金成分条件下相种类存在可能,并通过已有材料的相比例和相形貌实验结果分析绘制的类Schaeffler相图的准确性和适用性.绘制的Fe-Mn-Al-C类Schaeffler相图可以直观地提供不同合金成分所对应的相比例、相种类等信息,可用于新型含铝低密度钢的合金设计.      

简单共晶系相图的计算机计算

根据热力学原理和热力学数据，用计算机计算和绘制了一些简单共晶系相图，并用计算机打印相应的部分相图数据。     

基于化学平衡和渣相图的中、低碳锰铁生产工艺物料平衡计算

根据质量守恒和化学反应平衡原则,结合渣系相图以及生产中、低碳锰铁的台架试验数据,寻求一种计算精确度更高的适合中、低碳锰铁生产工艺的配料计算方法,该方法主要运用于摇包硅热法生产工艺流程的设计。     

微量Fe对半连续铸造锡青铜组织性能的影响

采用相图计算和组织观察法,研究了在锡青铜添加Fe元素对半连续铸造合金组织性能的影响.研究结果表明:经过相图计算发现,FeCu与P的中间相抑制了Cu3Sn从基体中的析出;铁元素的加入起到了明显的细化晶粒的作用,柱状晶明显减少,降低了因柱状晶产生的组织应力,提高了后续的加工性能;低锡铁青铜的抗软化性能与高锡青铜的相当.     

轧机灭火设计计算和管路压力降计算方法探讨

主要介绍了有色金属加工厂采用二氧化碳灭火系统的必然性和二氧化碳的物相图,轧机区、主地沟、工艺地下室、板式过滤机四大保护区各采用何种灭火方式,以及各区CO2设计用量的计算方法、应用条件、联动关系,还介绍了喷头布置、管路布置、流量计算、管路压力降计算方法等及注意事项。     

根据二元合金相图计算脱氧元素的熔化热

根据9幅二元合金相图，分别计算了6种炼钢用脱氧元素Si、Ca、Ba、Mn、La和Al的熔化热。根据二元合金相图计算脱氧元素的熔化热的方法，对确定出钢温度和钢水脱氧过程的热力学分析及计算有一定的实际意义。     

基于相图和组织控制的先进材料开发

Recent progress on research activities of phase diagrams in our laboratory has been presented. Experimental studies and thermodynamic calculations based on CALPHAD (Calculation of Phase Diagrams) method have been conducted in the following alloy systems. 1. Database on microalloying steels including carbide, nitride and sulfide is now being constructed. 2. ADAMIS (Alloy Database for Micro-Solders) containing 8 elements of Ag, Bi, Cu, In, Sb, Sn, Zn and Pb hasbeen constructed, which can handle all combinations of these elements and all composition ranges. 3. A thermodynamic database of Cu-base alloys including Cu-X binary system and Cu-Fe, Cu-Ni, Cu-Cr base ternarysystems has been constructed. 4. Experimental and thermodynamic calculations on Fe, Ni, Co and Ti aluminides have been conducted. 5. Experimental and thermodynamic calculations on Co base magnetic recording media have been conducted. 6. Thermodynamic analysis of interaction between magnetic and chemical orderings has been performed. By utilizing the information on phase diagrams, the following advanced materials have been developed. (A) New type of high speed steel with high hardness about Hv≈1000 by carbide dispersion carburizing method, (B) New Pb-free machinable stainless steel using titanium carbosulphide. (C) New Pb-free solder for Die-attaching use. (D) Shape memory alloys; Cu-base, Ferromagnetic Ni-base and Fe-base. (E) Invar alloys. (F) Egg-type powder. Typical examples of phase diagrams, phase stability, database and its application for the development of advanced materials will be presented.     

Development of a thermodynamic database for cemented carbides for design and processing simulations

Carbonitrides have a wide range of applications in demanding conditions that require high-temperature resistance, hardness, and strength. The technique to manufacture high-quality products based on such materials, e.g., cemented carbides, has been developed over the years. The experience of the well-known thermodynamic databases for steels has shown possibilities to improve material properties by calculations. Following the CALPHAD approach and using the PARROT module of the Thermo-Calc software, the development of a new database for cemented carbides containing Co-W-Ti-Ta-Nb-C-N has started. The stepwise creation of the database from experimental and theoretical information is presented. To illustrate the usefulness of the new database, some material processing predictions will be calculated. This article is based on a presentation made at “The Milton Blander Symposium on Thermodynamic Predictions and Applications” at the TMS Annual Meeting in San Diego, California, on March 1–2, 1999, under the auspices of the TMS Extraction and Processing Division and the ASM Thermodynamics and Phase Equilibrium Committee.     

材料设计中的结构层次理论及跨尺度关联问题

结合图、表和公式综述了材料设计从宏观到微观的不同层次理论的研究现状,包括连续介质力学、结构动力学、缺陷动力学、分子动力学和量子力学等,其中,量子力学属于微观层次,分子动力学主要属于介观层次,其余属于宏观层次;进而讨论了材料设计领域的构建材料结构与性质关系、以及沟通与整合各层次理论的跨尺度关联问题.最后,介绍了现阶段材料设计的知识库和数据库技术、专家系统技术、计算机模拟技术和纯理论计算方法等4种途径.     

Computation of Ni-Cr phase diagramvia a combined first-principles quantum mechanical and CALPHAD approach

A first-principles quantum-mechanical computational code has been used to compute the energy of formation for selected ordered and topologically close-packed (TCP) phases in a Ni-base alloy. The thermodynamic data are incorporated into an existing database for Ni alloys and used in conjunction with the CALPHAD approach to compute the binary Ni-Cr phase diagram. In addition, a thermodynamic model is used to treat long-range ordering and the formation of the Ni₂Cr. The phase field for ordering is compared against that predicted by the Thermo-Calc to elucidate possible implications on the long-term phase stability of Ni-base alloys in a nuclear waste repository environment.     

Temperature–Composition Dependence of Thermodynamic Mixing Functions of Co–Cr–Cu–Fe–Ni Melts

Powder Metallurgy and Metal Ceramics - In the framework of the CALPHAD method, a thermodynamic database was developed for calculating the thermodynamic properties of liquid alloys in the...     

Accelerated Design of Eutectic High Entropy Alloys by ICME Approach

Eutectic high entropy alloy with seven components is designed based on the integrated computational materials engineering (ICME) framework. The framework includes thermodynamic prediction using calculation of phase diagrams (CALPHAD), microstructure simulation using phase-field method, and experimental validation. The designed alloy shows the eutectic structure consisting of FCC and laves phase in the composition range from 8.25 to 10 at. pct Ta. The simulation and experimental results are co-related and a framework is proposed that can be used for high entropy alloy design subjected to various manufacturing processes.