The growth of alumina/YAG eutectic fibres by the laser-heated floating zone process

摘要

The development of Ceramic Matrix Composite (CMC) materials capable of operating at temperatures of 1400°C and above would be of great benefit to the power generation industry in terms of improved efficiency and reduced NO{sub}x emissions. A keycomponent of a high temperature CMC is a ceramic fibre which retains high strength and creep resistance at temperatures greater than 1400°C. Single crystal fibres of alumina and YAG are potential candidates, but Al{sub}2O{sub}3/YAG eutectic fibres havethe potential for higher fracture toughness and improved strengths at elevated temperatures. Continuous Al{sub}2O{sub}3/YAG eutectic fibres have been grown using the laser-heated floating zone (LHFZ) technique. The effect of fibre drawing rate on thescale and orientation of the eutectic microstructure has been investigated for three different feed materials. Fibres and feed stock have been characterised by x-ray diffraction, optical microscopy and scanning electron microscopy. Room temperaturetensile strengths have also been measured.