Paper number 782

BRIDGING MECHANISMS IN FIBRE-REINFORCED TI MMCS

Jun Liu¹ and Paul Bowen¹

1IRC in Materials for High Performance Applications/School of Metallurgy and Materials,
The University of Birmingham, Birmingham, B15 2TT, UK
E-mail: j.liu.mes@bham.ac.uk and p.bowen@bham.ac.uk

Summary

The physical nature of fibre bridging in a Ti?21s/SCS-6 composite has been studied by using in-situ SEM observations under tension. Based on these in-situ SEM observations, a bridging model has been developed which includes effects of Poisson's ratio on interfacial shear stresses. Excellent agreement is found between predicted crack opening displacements (CODs) and in-situ SEM measurements. A method is then proposed to determine the interfacial shear stress by considering the average stress sustained by bridging fibres. The method also illustrates good agreement between predictions and experimental measurements reported in the open literature. Finally, crack closure at the crack tip and its possible effects on stress intensity factor range in the matrix of Ti MMCs are also addressed.

Keywords

titanium-matrix composites, fibre-reinforced composites, silicon carbide, fibre bridging, in-situ SEM, crack opening displacement, modelling.