AbstractThe chevron notch testpiece geometry has been used in three and four point bending to evaluate the toughness of silicon carbide and silicon carbide reinforced with particulate titanium diboride. The toughness values obtained do not appear to depend either on initial chevron notch depth m the range 0·2≤αo≤0·4 or on chevron notch included angle in the range 40≤θ≤120°. This testpiece geometry allows relatively subtle effects of reinforcement in increasing the toughness of the monolithic material to be assessed with confidence. It also provides a convenient method of measuring toughness over a wide range of test temperatures.MST/1595