EFFECT OF INTERFACIAL SHEAR-STRENGTH ON MECHANICAL PROPERTY OF SIC SIC/

In order to quantitatively evaluate mechanical properties of fibers, m atrices and their interfaces in fiber reinforced SiC/SiC composites, n ano-indentation tests have been carried out. Using the same technique, fiber push-out test was performed. The specimens were analyzed by mea ns of scanning electron microscopy (SEM), before and after indentation tests. From the indentation load vs. displacement relations, the fibe r pushed out process has been discussed and the initiation loads of in terfacial debonding and those of interfacial sliding were defined and were discussed in comparison with the C/C composites. The load of inte rfacial debonding initiation was likely to increase in proportion to t he fiber circumference. The initiation load of interfacial sliding inc reased with increment of contact area between fiber and matrix. The re lation between bending strength and interfacial shear strength of SiC( pcs)/SiC(CVI) is preliminary postulated together with crack initiation and propagation characteristics and microstructural characteristics o f the composites.