Compressive testing of ceramics

Abstract

Research has been conducted towards the development of a compressive test method more suitable than present procedures for use on advanced ceramics with extremely high compressive strength. A dumb-bell-shaped specimen is proposed as an edge-effect-free shape, and test equipment with a self-aligned system is suggested to estimate accurately the compressive strength. Experimental results for some structural ceramics indicate the following: (1) the columnar specimen prescribed in the Japanese Industrial Standards has edge effects, whereas a dumb-bell-shaped specimen has no edge effect and shows higher strength than the columnar specimen; (2) acoustic emission events are detected at an early stage of the compressive load, and the behaviour coincides with the initiation of the crack propagation under compression; (3) an isolated crack on the specimen surface of ceramics with a fine matrix has little influence on compressive strength. © 1994.