A high-temperature fibre testing facility

A multiple-unit fibre tester with a controlled environment and fully computerized data acquisition and control has been designed and constructed to study the thermomechanical behaviour of fibres at high temperatures. High temperatures are achieved by a self-resistance heating technique, strains are estimated from displacement measurements using LVDTs, while temperature is measured using a two-colour infrared pyrometer. In the determination of displacements 0.25 mu m can be resolved, while temperature stability can be achieved over long periods of time. The temperature difference between the hottest and coldest points in the hot zone was minimized to 30 degrees C at 1500 degrees C by combining appropriate values of gas flow rates and fibre gauge lengths. Examples of creep and thermal expansion measurements are presented for SCS-6 SiC fibres over the temperature interval of 900-1500 degrees C.