(中南大学 粉末冶金国家重点实验室, 长沙 410083)
摘 要: 概述了金属-Si-C体系界面反应和相稳定图的研究近况以及用Thermo-Calc软件计算相稳定图的局限性； 阐明在相平衡条件下由化合物的Gibbs生成自由能计算活度的原理。通过将相稳定图分解为4种拓扑结构并使用相标号的方法, 得到适用于三元系中存在线性化合物的相稳定图的算法, 并利用Matlab语言编写相稳定图的计算和绘图程序。 使用者只需将相平衡信息和化合物的Gibbs生成自由能写入普通的文本文件, 即可快速得到所需体系的相稳定图。以Cr-Si-C和Nb-Si-C三元系为例, 分别计算1 000 ℃和1 300 ℃的相稳定图并讨论其在分析和判断扩散通道方面的应用。
关键字: 金属-Si-C体系；碳化物； 相稳定图； 活度； 固态反应
（State Key Laboratory of Powder Metallurgy,
Central South University, Changsha 410083, China）
Abstract: The current understanding on the interface reactions and the phase stability diagrams in the metal-Si-C systems were reviewed. The principle for deriving activities from the Gibbs energy of formation for compounds was described. Splitting the phase stability diagram into four topological structures and using the phase mark method, a new approach was built up to calculate the phase stability diagrams of ternary systems with stoichiometric binary and ternary compounds. Consequently, a program for calculating and plotting the phase stability diagrams was developed by utilizing the programming language of Matlab. Users can get the phase stability diagram immediately after only importing the phase equilibria information and Gibbs energy of formation for compounds into txt format documents. The method and program developed in this work were successfully applied to the Cr-Si-C and Nb-Si-C systems at 1 000 ℃ and 1 300 ℃, respectively. The computed diffusion paths agree reasonably with the experimentally observed ones.
Key words: metal-Si-C system; SiC; phase stability diagram; activity; solid-state reaction
