A uniaxially reinforced zircon-silicon carbide composite

Abstract

Zircon matrix composites uniaxially reinforced with as-supplied and BN-coated silicon carbide filaments were fabricated, and their mechanical properties were measured in flexure mode. A toughened-composite behaviour was displayed by the reinforced samples with strengths between 681 and 700 MPa and toughness between 24 and 41 kJ m⁻². In comparison, the monolithic zircon failed in a brittle manner, had an average strength of 280 MPa and toughness of 0.95 kJ m⁻². Influence of fibre-matrix interfacial shear stress on the first matrix cracking stress, ultimate failure strength and strain, toughness, and mode of failure were studied. The composite toughness was found to be dependent on the interfacial shear stress whereas the first matrix cracking stress was independent of the interfacial shear stress. These results on mechanical properties are compared with predictions from composite models.