STP1077: Relationship between Acoustic Emission and Flaw Size in Si3N4 Ceramics

    Mori, Y
    associate professor, College of Industrial Technology, Nihon UniversityResearch Center for Advanced Science and Technology, The University of Tokyo, Narashino, ChibaMeguroku, Tokyo,

    Kishi, T
    associate professor, College of Industrial Technology, Nihon UniversityResearch Center for Advanced Science and Technology, The University of Tokyo, Narashino, ChibaMeguroku, Tokyo,

    Pages: 10    Published: Jan 1991


    Abstract

    Acoustic emission behavior was investigated in the Si3N4 ceramics in order to study the effect of flaw size on fracture strength. A close relation between the generation of acoustic emission and flaw size was found. It was found that acoustic emission signals can be detected only just before specimen failure with flaw size of 15 μm,1 a critical flaw size estimated for the materials, or larger. Whereas flaws smaller than 15 μm began to generate emissions at the stress level, approximately 50 % of the strength of the specimens failed. In the latter case, it was concluded that emissions were due to microscopic fracture events around inherent flaws.

    Keywords:

    acoustic emission, silicon nitride, artificial flaw, flaw size, nondestructive test, fracture


    Paper ID: STP19097S

    Committee/Subcommittee: E07.04

    DOI: 10.1520/STP19097S


    CrossRef ASTM International is a member of CrossRef.