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M: Metallphysik

M 1: Plastizität I

M 1.9: Vortrag

Montag, 27. März 2000, 12:30–12:45, H16

Plastic deformation of cubic zirconia single crystals — •Aleksander Tikhonovsky, Martin Bartsch, and Ulrich Messerschmidt — Max-Planck-Institut fuer Mikrostrukturphysik, D-06120 Halle/Saale

Cubic zirconia is used as a matrix material in two-phase zirconia ceramics. While its plastic deformation along the [112] direction, which activates the 1/2[110]001 easy slip system, has been thoroughly investigated previously, deformation properties in [100] direction, where the easy slip system has a zero orientation factor, are quite unclear. Cubic zirconia single crystals have been compressed along the [100] direction in air. Except at the highest temperatures (1400 degC), the flow stress along [100] is higher than that along [112]. The strain rate sensitivity is always higher along [100] but shows a minimum near 1000 degC, indicating three temperature ranges: a recovery-controlled high-temperature range above 1100 degC, an intermediate athermal range from 1100 degC to 700 degC, and a low-temperature range down to the lowest temperature of the experiments (500 degC), where lattice friction is a dominating process. A TEM analysis showed that dislocations glide mainly on 110 slip planes. The quantitative differences between the data of both compression directions are certainly due to the different lattice resistance on the different slip planes that are activated.