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 degrees C for 1 h, the Yb2Si2O7 was grown in situ on the fiber surface, forming an interphase layer. Then, SiCf/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 SiCf/Yb2Si2O7/SiC minicomposites with Yb2Si2O7 interphase was significantly higher than SiCf/SiC minicomposites without interphase. The crack deflection, interfacial debonding, and fiber pullout were observed in the tensile fracture of the SiCf/Yb2Si2O7/SiC minicomposites.