Preparation and mechanical behavior of Yb2Si2O7 interphase in SiCf/SiC minicomposites

In this work, the Yb₂Si₂O₇ interphase was prepared on SiC fibers using the sol–gel method. The influence of sol concentration on the morphology of the interphase was discussed. After heat treatment in argon at 1200°C for 1 h, the Yb₂Si₂O₇ was grown in situ on the fiber surface, forming an interphase layer. Then, SiC_f/Yb₂Si₂O₇/SiC minicomposites were prepared by chemical vapor infiltration (CVI). The Yb₂Si₂O₇ interphase exhibited no changes throughout the high-temperature preparation process and maintained stability and compatibility with the fiber and matrix. The tensile strength of SiC_f/Yb₂Si₂O₇/SiC minicomposites with Yb₂Si₂O₇ interphase was significantly higher than SiC_f/SiC minicomposites without interphase. The crack deflection, interfacial debonding, and fiber pullout were observed in the tensile fracture of the SiC_f/Yb₂Si₂O₇/SiC minicomposites.