SiC/Ti基复合材料界面反应的热力学研究

Thermodynamic Studies on Interfacial Reactions in SiC-Fibre Reinforced Ti-Matrix Composites

通过建立热力学可能反应模型,分别计算了SCS-6SiC长纤维增强Ti3Al和TiAl金属间化合物基复合材料界面反应的Gibbs函数变值△rG,并用△rG判据推测了界面反应产物并与透射电镜实验结果进行了对比分析。研究表明,由于TiAl中原子结合力较强,因而SCS-6SiC/TiAl复合材料的界面反应较轻。所研究的2种复合材料界面反应的二元反应产物为TiC,Ti5Si3和Ti3Si,Ti-Si相图中的其它二元硅化物不可能形成。

Possible chemical reactions at the interface of SCS-6 SiC/Ti3Al and SCS-6 SiC/TiAl composites were considered and the Gibbs function increments, Delta(T)G, were calculated for all the reactions. Results predicted by thermodynamic calculation were compared with experimental ones made by transmission electron microscopy(TEM). It is shown that the interfacial reaction in SCS-6 SiC/TiAl is not as severe as it is in SCS-6 SiC/Ti3Al. In both composites the fibre-matrix interfacial reaction results in the formation of binary compounds of TiC, Ti5Si3 and Ti3Si. The fact that the other silicides shown in Ti-Si phase diagram do not appear at the interface was discussed thermodynamically and was confirmed by the TEM observation.