STP1172

    Fracture Toughness Evaluation of Ceramic Bonds Using a Chevron-Notch Disk Specimen

    Published: Jan 1992


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    Abstract

    The chevron-notched diametrally compressed disk specimen has been used to measure the fracture toughness of zirconia/zirconia bonds and zirconia/nodular-cast-iron bonds. The data are reasonably consistent with experience obtained using monolithic ceramics. In particular, the strain energy release rate increases with increasing shear:tension ratio, and the opening-mode fracture toughness measured using the disks is generally within 20% of the value obtained with bend beams. However, the shear toughnesses of the bonds investigated are approximately 2.4 times the opening toughness, a ratio somewhat higher than that for monolithic ceramics. The high ratio can be attributed to rubbing of mutually opposed crack faces, deviation of the fracture plane into higher-toughness zirconia prior to instability for the ceramic/ceramic bonds, and shear of the braze-metal interlayer in the case of the metal/ceramic bonds.

    Keywords:

    fracture toughness, compression loads, shear stresses, disk specimen, chevron-notch specimen, partially stabilized zirconia, nodular cast iron, ceramic/ceramic bonds, metal/ceramic bonds


    Author Information:

    Rosenfield, AR
    Research leader and principal research scientist, Battelle Memorial Institute, Columbus, OH

    Majumdar, BS
    Research leader and principal research scientist, Battelle Memorial Institute, Columbus, OH


    Paper ID: STP24711S

    Committee/Subcommittee: E08.04

    DOI: 10.1520/STP24711S


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