SURFACE FATIGUE IN CERIA-STABILISED POLYCRYSTALLINE TETRAGONAL ZIRCONIA BETWEEN ROOM TEMPERATURE AND 1073K

Fatigue deformation and fracture were induced by pressing 120 degree hardened silver steel conical tips against a flat, polished CeTZP counterface between 293 and 1073 K with cyclic loads of 19.6 +/- 9.8 N, for up to 475000 cycles. The ground tips of the cones plastically deformed during the initial...

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Bibliographic Details
Published in:Journal of materials science 1995-01, Vol.30 (1), p.151-161
Main Authors: Guillou, M O, Henshall, J L, Hooper, R M
Format: Article
Language:English
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Summary:Fatigue deformation and fracture were induced by pressing 120 degree hardened silver steel conical tips against a flat, polished CeTZP counterface between 293 and 1073 K with cyclic loads of 19.6 +/- 9.8 N, for up to 475000 cycles. The ground tips of the cones plastically deformed during the initial loading cycle to produce a flattened end which conformed with the substrate. This test format is comparable to the service conditions of these types of ceramics. At temperatures up to and including 673 K, a tetragonal to monoclinic transformed zone is formed around the contact zone. This expands as the number of cycles is increased. Later in the fatigue process, grain lifting at the periphery of the contact zone causes intergranular pitting around the edge of the contact zone, followed by extension both away from and into the contact region. At 673 K and above, a small number (3-5) of radial intergranular cracks formed after a few cycles (less than or equal to 10) propagated a substantial distance away from the contact zone. 27 refs.
ISSN:0022-2461