HIGH TEMPERATURE CREEP OF OXIDE-FIBRE/METAL- MATRIX COMPOSITES UNDER VARIABLE LOADING

The present paper aims at testing a hypothesis of failing a relatively weak fibre/matrix interface under variable loading that yields an increase in steady state creep rate. The hypothesis is tested qualitatively by comparing the creep behaviour of composites with various interface strength values under the conditions mentioned. The hypothesis is tested semi-quantitatively by estimating the interface strength as a result of an event yielding an increase in creep rate. The latter needs to a usage of a microstructural creep model. Both approaches are used in the paper and the results support the hypothesis. Experimental data obtained are an additional argument to a necessity to develop metal matrix composites with a strong interface, which can be a base for real creep resistant composites with high temperature use.