Microcracking mechanism in a SiCf-SiBC composite creep-tested in argon

This paper addresses the creep behaviour of a woven SiCf-SiBC composite, te sted in tension under a partial pressure of argon, between 1273 K and 1473 K. It appears that the creep strain begins from 1273 It and becomes larger at higher temperatures. Moreover, the shapes of the creep curves led to the assumption of the existence of two competing deformation mechanisms depend ing on the temperature domain. The creep mechanism involved is microcrack d amage-creep. From higher resolution studies at higher scales (scanning elec tron microscopy, transmission electron microscopy (TEM) and high resolution electron microscopy (HREM)), many types of damage were observed, for examp le matrix microcracking, fibre/matrix debonding and fibre/matrix sliding. T he observations via TEM and HREM enabled us to specify the existence or not of the classical creep mechanism of the constituents of the composite, and also to characterize the behaviour and the role of the different interface s and especially of the pyrocarbon interphase, These multiscale observation s will be discussed in order to highlight the creep-damage mechanism as a f unction of temperature of the SiCf-SiBC composites.