Fracture of Si ₃ N ₄ –SiC Whisker Composites under Cyclic Loads

Abstract

This communication demonstrates the role of cyclic compressive loads in inducing mode I fatigue crack growth at room temperature in Si 3 N 4 matrix–SiC whisker composite materials containing stress concentrations. The characteristics of stable, cyclic fracture are examined for several volume fractions of the SiC whisker and are compared with those of the matrix material. It is found that the composites with higher volume fractions of SiC whiskers exhibit an inferior resistance to fracture under cyclic compressive loads despite improvements in fracture toughness values.