Preparation and mechanical behavior of Yb ₂ Si ₂ O ₇ interphase in SiC _f /SiC minicomposites

Abstract In this work, the Yb 2 Si 2 O 7 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 Yb 2 Si 2 O 7 was grown in situ on the fiber surface, forming an interphase layer. Then, SiC f /Yb 2 Si 2 O 7 /SiC minicomposites were prepared by chemical vapor infiltration (CVI). The Yb 2 Si 2 O 7 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 /Yb 2 Si 2 O 7 /SiC minicomposites with Yb 2 Si 2 O 7 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 /Yb 2 Si 2 O 7 /SiC minicomposites.