Narrow Results

This paper describes the investigation of bending strength and elastic wave signal characteristics of Si₃N₄ monolithic and Si₃N₄/SiC composite ceramics with crack healing ability. The elastic wave signals, generated during the compression load by a Vickers indenter on the brittle materials, were recorded in real time, and the AE signals were analyzed by the time-frequency analysis method. The three-point bending test was performed on the Si₃N₄ monolithic and Si₃N₄/SiC composite ceramic specimens with/without crack-healed. Consequently the bending strength of the crack-healed specimens at 1300°C was completely recovered up to that of the smooth specimens. And the frequency properties of crack-healed specimens tended to be similar to the distribution of the dominant smooth specimens frequency. This study suggests that the results of the signal information for the anisotropic ceramics show a feasible technique to guarantee structural integrity of a ceramic component.