The enhanced mechanical properties of SiC nanowires/Ba _0.75Sr _0.25Al ₂Si ₂O ₈ ceramics with embedded SiO ₂ interface

Abstract

In this work, low-softening-temperature and low-modulus SiO2 was introduced as an embedded interface between SiC nanowires (SiCnws) and the BaxSr1−xAl2Si2O8 ceramic matrix to enhance the strength and toughness of the ceramic. In the sintering process, molten SiO2 enhances the flowability of the ceramic powders and modifies the dispersion of the SiCnws. The strengthening effect of SiCnws was fully realized, and the flexural strength of the optimized ceramics reaches 193±16 MPa, which represents an increase of 52.6%. After the formation of the embedded SiO2 interface with a low modulus, cracks can deflect along the SiCnws surface, which is consistent with the criterion of He and Hutchinson. This can effectively extend the crack propagation path, and the fracture toughness is thus improved by 94.0%, reaching 3.1±0.5 MPa• m 1/2 .