(中南大學 粉末冶金國家重點實驗室, 長沙 410083)
摘 要: 概述了金屬-Si-C體系界面反應和相穩(wěn)定圖的研究近況以及用Thermo-Calc軟件計算相穩(wěn)定圖的局限性； 闡明在相平衡條件下由化合物的Gibbs生成自由能計算活度的原理。通過將相穩(wěn)定圖分解為4種拓撲結構并使用相標號的方法, 得到適用于三元系中存在線性化合物的相穩(wěn)定圖的算法, 并利用Matlab語言編寫相穩(wěn)定圖的計算和繪圖程序。 使用者只需將相平衡信息和化合物的Gibbs生成自由能寫入普通的文本文件, 即可快速得到所需體系的相穩(wěn)定圖。以Cr-Si-C和Nb-Si-C三元系為例, 分別計算1 000 ℃和1 300 ℃的相穩(wěn)定圖并討論其在分析和判斷擴散通道方面的應用。
關鍵字: 金屬-Si-C體系；碳化物； 相穩(wěn)定圖； 活度； 固態(tài)反應
（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
