Development of Thermodynamic Model on Phase Diagram Database

相图数据库热力学模型的开发

基本信息

批准号：
11694124
负责人：
ISHIDA Kiyohito
金额：
$ 4.1万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

It is well known that magnetic properties such as the Curie temperature and the mean magnetic moment of ordered compounds have different values from those of disordered solutions. In consequence, the stability of the ordered phase is depressed (enhanced) due to the interaction between the chemical and magnetic ordering caused by the decrease (increase) of magnetic properties. In this project, a new thermodynamic model taking into account the interaction effect was developed by the collaboration with prof. Bo Sundman in the Royal Institute of Technology, Sweden. Model calculations to describe the phase stability of the b.c.c. and f.c.c. structures were performed taking into account the magnetic and the chemical ordering reactions and also the mutual interaction between them. Thermodynamic assessments of the Fe-X (X=A1, Ni and Co) systems were also carried out using two- or four-sublattice s-CEF, including the interaction effect. These calculations lead to the following conclusions.(1) The incomprehensible A2+B2 phase separation and tricritical point in the Fe-Al system originate in the depressed chemical and magnetic ordering energies caused by the mutual interaction.(2) The stability of both γ'-FeNi_3 (L1_2) and γ"-FeNi (L1_0) compounds is strongly enhanced by the additional magnetic energy due to the chemical ordering. The calculated phase diagram suggests that the γ"-FeNi (L1_0) phase is stable.(3) In the Fe-Co system, the stability of the B2 ordering arises mostly from the enhanced magnetic energy due to the chemical ordering.

众所周知，诸如Curie温度和有序化合物的平均磁矩等磁性特性与无序溶液的值不同。因此，由于磁性特性下降（增加）引起的化学和磁性顺序之间的相互作用，有序相的稳定性被抑郁（增强）。在这个项目中，考虑到相互作用效果的新热力学模型是由与教授合作开发的。瑞典皇家理工学院的Bo Sundman。描述卑诗省的相位稳定性的模型计算和F.C.C.考虑到磁性和化学有序反应以及它们之间的相互作用，进行了结构。 Fe-X（X = A1，Ni和CO）系统的热力学评估也使用了两种或四个公共的S-CEF，包括相互作用效应。这些计算得出以下结论。（1）Fe-Al系统中无法理解的A2+B2相分离和小型距离造成的化学和磁有序能量是由相互相互作用引起的。（2）γ'-Feni_3（L1_2）和γ“ -feni（L1__0）的稳定性均具有强大的化学效果，因此均具有强大的化学效果。计算出的相图表明，γ“ -feni（L1_0）相是稳定的。（3）在Fe-Co系统中，B2排序的稳定性主要是由于化学排序引起的增强的磁能。