Crack Initiation and Arrest in a SiC Whisker/A1 ₂ O ₃ Matrix Composite

Abstract

The fracture initiation and arrest stress intensity factors were determined for a SiC‐whisker‐reinforced AI 2 O 3 matrix composite. A chevron‐notched, three‐point‐bend specimen was used to genera e the load/displacement curve, which exhibited repeated crack initiation, followed by crack arrest behavior. Corresponding stress intensity factors were determined for both situations using the compliance technique. Calculated crack arrest positions were in agreement with fractographic observations. Both the crack arrest and the crack initiation stress intensity factors exhibited a rising R ‐curve with increasing crack length, suggesting the presence of wake toughening effects on the crack growth resistance.