Oxide-Fibre/Titanium-Aluminide-Based Composites: Microstructure and High Temperature Creep

摘要

An obvious necessity to have light materials for temperature interval 800 ― 1000°C yields to the development of titanium-aluminide-matrix composites. The most advanced family of such composites is that based on SiC-fibres normally modified to prevent a fibre/matrix interaction on the interface. Such composites have been studied and documented sufficiently well. However, temperature limitations in using the composites caused by both the interaction mentioned and fibre recrystallization make using more stable fibres such as single crystalline oxide fibres being attractive. But certainly due to the absence of appropriate fibres, only some indications of the possibilities arising as a result of combining oxide fibres can be found in literature. In the present paper, stimulated by the availability of single crystalline oxide fibres produced by using the internal crystallization method (ICM) in such a way as to ensure the fibre cost sufficiently low for structural applications, ICM-sapphire fibres were introduced into Ti-Al-based matrices by using pressure casting. Creep tests were performed at temperatures beyond those normally considered for titanium aluminide alloys.