Effects of Oxidation and Oxidation Under Load on Strength Distributions of Si ₃ N ₄

Abstract

The room‐temperature strength distributions of a sintered and a hot‐pressed Si 3 N 4 were examined in the as‐machined condition, after oxidation at 1370°C and after oxidation under load at 1370°C. The strength‐controlling flaw populations were highly transient in nature. Both the duration of oxidation and the magnitude of the applied load were observed to effect changes in strength. This dynamic situation is related to both strengthening and weakening processes, which at times may occur simultaneously in the same strength distribution.