Strong interface in CMCs, a condition for efficient multilayered interphases
- Univ. de Bordeaux, Pessac (France). Lab. des Composites Thermostructuraux
A fiber treatment was used to change the bonding strength of the Nicalon NLM 202 SiC fiber from weak to strong, in a series of 2D-SiC/SiC composites with multilayered interphases. The materials with the pre-treated fibers were compared to the same materials but reinforced with as received fibers. The stress-strain behavior and the fracture toughness were examined as a function of rack patterns identified by TEM. All the materials could be grouped into two distinct families: (1) materials reinforced with untreated fibers have a weak fiber bonding and are characterized by a low strength and a low toughness and (2) materials with the pre-treated fibers have a strong fiber bonding and are characterized by a high strength and a high toughness. This latter behavior is identified by TEM. It corresponds to a new interfacial behavior with a cohesive mode of interfacial cracking, involving branching and deflection by the successive interfaces. In the former family, the adhesive interfacial failure mode corresponds to the classical debond/sliding mechanism.
- OSTI ID:
- 100577
- Report Number(s):
- CONF-941144--; ISBN 1-55899-266-9
- Country of Publication:
- United States
- Language:
- English
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