The evolution of mechanical and structural properties at the fiber/matrix interphase of SiC/SiC composites

Fiber/matrix interfacial strength is known to play an important role in the mechanical properties of SiCf/SiC composite. The understanding of the deformation mechanism of the fiber/matrix interphase under stress is important in application of SiCf/SiC composite. In the present work, we employ molecular dynamics simulations to investigate the shear strength and structural evolutions of fiber/matrix interphase of SiCf/SiC composite in atomic scale. It is revealed from our computational study that the interphase of graphite-like pyrolytic carbons are the weakest part in the interphase, which determines the interfacial mechanical properties. It is also found that an obvious drop of shear strength occurs at high temperature, owing to the Wigner energy release in the graphite-like carbons. (C) 2015 Elsevier B.V. All rights reserved.