R ‐Curve Behavior of Silicon Nitride–Titanium Nitride Composites

Abstract

The R –curve for Si 3 N 4 −40 wt% TiN composites was estimated by the indentation‐strength method and compared to that of monolithic Si3N4 with duplex microstructure. Both materials exhibited rising R ‐curve behavior. The Si3N4‐TiN composites, however, displayed better damage tolerance and higher resistance to crack growth. From TEM observation, it was inferred that this superior performance of Si 3 N 4 ‐TiN composites can be attributed mainly to stress‐induced microcracking at hete rophase (Si 3 N 4 /TiN) boundaries.