Construction of CePO4 weak interface in 3D continuous fiber-reinforced Al2O3 composites for enhanced mechanical performance

Abstract

Oxide fiber-reinforced oxide ceramic matrix composites (OF/OCMs) with higher fracture toughness, higher strength and higher thermal stability property is the future trend. The interface between fiber and matrix dominates the mechanical performance of the composites, and is crucial for enhancing the mechanical performance of the OF/OCMs. Hence, a novel CePO4 interface was designed and fabricated in the continuous Al2O3 fiber (Al2O3f) reinforced Al2O3 composites by sol-gel method in this paper. The effects of CePO4 interface on the morphology and mechanical properties of the Al2O3f/Al2O3 composites were systematically investigated. The Al2O3f/CePO4/Al2O3 composites showed a ductile fracture behavior up to 1200 °C, while the Al2O3f/Al2O3 composites demonstrated pronounced brittle fracture characteristics. CePO4 as a weak interface is favorable for inducing crack deflection and fiber pullout in the Al2O3f/CePO4/Al2O3 composites, conferring superior damage tolerance to the composites. The flexural strength of Al2O3f/CePO4/Al2O3 composite sintered at 1200 °C was 182.62 MPa, representing a 12.3 % increase compared to the Al2O3f/Al2O3 composite, indicating that the Al2O3f/CePO4/Al2O3 composites have a broad application prospect in oxidation and high-temperature environments as a high-temperature structure material.