Abstract :
Interfacial strength of Ti b 21S/SCS 6
composite was increased via ageing. Composite specimens
with ao/W ratios of 0.24 and 0.07 were prefatigued
in three point bending at ambient and at 500 C
both in the air and vacuum. Bridging fibres were
extracted from the pre-fatigued specimens and tested
in tensile loading to monitor the strength degradation
due repeated opening and closing of the fatigue crack.
A tri-modal Weibull distribution was employed to
express strength distribution of the SCS 6 fibres.
Results have shown that cyclic loading of the composites
lower the mean tensile strength of the fibres by
20%, compared to the unfatigued composite. A
marked effect of initial unbridged defect size was
observed, when the tensile strength data were divided
into two sub-population using the fatigue crack length
values. Compared to unfatigued composite, tensile
strength reductions of 41 and 22% were measured from
the prefatigued composites with ao/W of 0.24 and 0.07,
respectively.
