Interfacial properties of multilayered interphases in SiC/SiC CVI-composites with weak and strengthened interfaces

摘要

The mechanical behavior of multilayered (C,SiC)n interphases in SiC/SiC composites was investigated using single fiber push-out tests. The composites were prepared with either as-received or treated SiC-based fibers (Nicalon). For the composites with as-recived fibers (weakly bonded fibers), interfacial characteristics are extracted from the non-linear part of the stress-displacement curve by fitting Hsueh's push-out model. The resistance to interface crack growth and fiber solding increases with the number of (C,SiC) sequences. For the composites with treated fibers (strongly bonded fibers), the push-out curves exhibit an uncommon upward curvature which reflects different modes of interphase cracking and a contribution fiber roughtness.