Creep-related micromechanical behavior of zirconia-based ceramics investigated by nanoindentation

The creep-related micromechanical behavior of zirconia ceramics (ZrO2) was investigated by nanoindentation based on continuous stiffness measurements at different strain rates at room temperature. The elastic modulus was found to decrease continually and the hardness reached a constant value with increasing depth. Moreover, the elastic modulus and hardness both increased at a given indentation depth with increasing loading rate and exhibited similar trends. The creep strain rate sensitivity was independent of the loading rate. The primary deformation mechanism is grain boundaries sliding accompanied by intergranular dislocation due to the existence of amorphous phases in the grain boundaries. Meanwhile, the mechanism of stress-directed diffusion acts an important role during the creep process.