INTERFACE CONSIDERATIONS IN HIGH-TEMPERATURE TITANIUM METAL-MATRIX COMPOSITES

Near-alpha titanium alloys are of interest for continuous fibre reinfo rced titanium-based composites owing to their better creep resistance than other titanium alloys. The main advantage of these matrices is th at they can improve transverse properties of the composite at high tem perature. However, cracking at the fibre/matrix interface in the as-co nsolidated condition has been reported with some near-alpha matrices. Two composites were compared in the present work: SCS-6/Ti-6-2-4-2 and SCS-6/IMI 834. Very few defects were detected in the SCS-6/Ti-6-2-4-2 composite whereas an extensive cracking of interfibre spacings was ob served in the SCS-6/IMI 834 composite manufactured in the same conditi ons. Our investigations revealed that the zone is very similar in both region cannot explain the brittle behaviour of the IMI 834 matrix, It has been established that cracking of the SCS-6/IMI 834 composite res ults from a combined effect of thermal residual stresses and matrix mi crostructure.