Superplastic Deformation Behavior of Undoped and Doped High-Purity 3Y-TZP

Abstract

Superplastic deformation behavior was examined in undoped and doped high purity 3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) with fine and coarse grains. In undoped 3Y-TZP, fine grain materials below 0.3 μm showed two deformation regions with a stress exponent of two, a grain size exponent of one and an apparent activation energy of 370 kJ/mol at high stress region and three, one and 630 kJ/mol at low stress region, while coarse grain materials above 1 um showed two deformation regions with a stress exponent of one, a grain size exponent of three and an apparent activation energy of 450 kJ/mol at high stress region and three, one and 550 kJ/mol at low stress region. On the other hand in alumina doped high purity 3Y-TZP, both the fine and coarse grain materials showed two deformation regions with a stress exponent of one, a grain size exponent and an apparent activation energy of 520 kJ/mol at high stress region and two, one and 590 kJ/mol at low stress region. The region of diffusional creep region with a stress exponent of one was first observed in 3Y-TZP. Deformation mechanism maps have been drawn for undoped and doped TZP, and the obtained deformation mechanism maps can predict these deformation regions.