Creep rupture of [90](8) Sigma fibre reinforced titanium matrix composite

The transverse creep rupture of Ti-6-4, reinforced with Sigma SM1140 + SiC fibre, has been studied at 450 and 600 degreesC. In all cases the rupture l ives are found to be lower than for the monolithic Ti-6-4 alloy. At 450 deg reesC in the high/medium stress regime, where interfaces fail on load-up, i ntergranular failure of the matrix occurs. This is caused by oxidation dama ge and its severity increases as the rupture time increases. At low stress, however, where interfaces do not fail on load-up, intergranular failure is reduced due to the lack of an easy oxygen diffusion path. At 600 degreesC, fracture surfaces from the high/medium stress regime do not exhibit the in tergranular failure observed at 450 degreesC. At low applied stress at 600 degreesC, however, the TMC exhibits signs of severe oxidation damage in the form of attacked fibre/matrix interfaces and brittle matrix failure. Previ ously developed TMC creep rupture models have been assessed. The Wright-Cro ssman model is found to provide a good upper bound on the experimental data whilst the more recent John-Khobaib-Smith model provides a lower bound. Cr own Copyright (C) 2001 Published by Elsevier Science B.V. All rights reserv ed.