Strain Rate Dependence of Tensile Behavior and Environmental Effect in Zirconia Ceramics

抄録

The tensile strength of four kinds of zirconia ceramics (two kinds of Y-TZP with different grain sizes, Mg-PSZ and Ce-TZP) has been investigated for a wide range of strain rates (3×10⁻⁹−1.0×10⁻¹ s⁻¹) in both air and vacuum. The obviously unique strain rate dependence was observed in Y-TZPs and Mg-PSZ, which have anelastic properties. On the other hand, such strain rate dependence was not observed over the whole range of strain rates for Ce-TZP, which does not exhibit anelasticity. For all of the samples investigated, there was no significant difference between both values of tensile fracture strength in air and vacuum. It was found that a decrease in strength with decreasing strain rate should not be associated with the static fatigue growth of microcracks nucleated during loading. It was concluded that the extent of the occurrence and the exhaustion of anelasticity predominantly controls the tensile strength of zirconia ceramics.