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(a) SEM of matrix cracking
(b) SEM of interface debonding and fiber breakage
Fig. 21.7 Fracture surface SEM of C/SiC
Fig. 21.8 Average energy distribution of different samples
B signals have a wide energy distribution and are generated throughout the creep
process, it may respond to debonding. The Class C have the highest energy, so these
class were attributed to the most important damage mechanisms observed in this type
of composite during the creeping: fibre failures with maybe fibre band failures.
AE signals can reflect the damage evolution during the entire creep period before
material failed, help to gain some insight into the high temperature creep behavior
of C/SiC. As shown in Fig. 21.9, different damage modes accumulate with creep
lifetime, they are derived from samples with long (Fig. 21.9a), medium (Fig. 21.9b),
and short (Fig. 21.9c) creep lifetime respectively. The creep damage evolution of this