DISLOCATION VELOCITIES IN CUBIC ZIRCONIA (ZRO2) SINGLE-CRYSTALS

Dislocation velocities between 1100 and 1450 degrees C in 9 . 4 mol.% Y2O3 fully stabilized cubic ZrO2 single crystals were studied using the stress pulse-etch-pit technique. The stress and temperature dependences of the edge and screw dislocation velocities were measured at engineering stresses from 60 to 185 MPa. The activation energy for motion of the edge dislocations (5 . 0 +/- 0 . 4 eV) is slightly lower than that for screw dislocations (5 . 6 +/- 0 . 6 eV). At the lower end of the temperature range, the stress exponent m of the edge dislocation velocities is close to unity but increases modestly (to about 3 . 6) with increasing temperature. With reasonable choice of parameters, the data can be attributed to a Peierls potential, to jog dragging or to solute pinning.