High-temperature plastic deformation of Er2O3-doped ZrO2 single crystals

The high-temperature plastic deformation of 5 mol% Er2O3-doped ZrO2 monofilaments and rods processed by the laser-heated floating-zone method was studied using tensile and compression tests. The microstructure of the as-fabricated and plastically deformed crystals was characterized by scanning and transmission electron microscopy. The crystals were formed by a fine distribution of nanometer-sized tetragonal variants with the c-axes mutually perpendicular, this particular microstructure being a consequence of the fast quenching associated with the fabrication process. A model is proposed to analyze the interaction between dislocations gliding in the multiple {1 0 0}〈0 1 1〉 slip planes and the interaction of dislocations with the tetragonal variants, taking into account the peculiar microstructure of the material. The model explains the high work hardening observed in the system, the formation of unique plasticity-induced defects, and the high-temperature fracture mechanisms. These issues are discussed in comparison with previous studies of yttria-doped partially stabilized zirconia.