Ferroelastic Domain Switching in Polydomain Tetragonal Zirconia Single Crystals

Abstract

As-received, yttria-doped (4.2 wt % Y203) single crystals of zirconia were heated to ?21OO0C in air. Cube-shaped samples with faces perpendicular to (100) axes on the basis of the pseudocubic symmetry were cut from the cryst:als. X-ray and electron diffraction indicated that the crystals are polydomain with [OOl] axes, on the basis of the tetragonal symmetry, in three mutually orthogonal directions (pcerpendicular to the cube faces). The cube-shaped crystals were tested in compression at temperatures as high as 1400°C. X-ray diffraction indicated that ferroelastic domains underwent reorientation (switching) in compression. Subsequently, notched samples with the long direction of the beams along (100) on the hasis of the pseudocubic symmetry were fractured in three-point bending at temperatures as high as 1000°C. X-ray diffraction from fracture surfaces showed that domain reorientation had occurred and that no monoclinic phase was observed on fracture or ground surfaces. The fracture toughness at room temperature and at 1000°C was -12 and -8 MPa . m"*, respectively. Preliminary experiments on po1:ycrystalline tetragonal zirconia samples containing 5.4 wt% Y 2 0 3 and sintered at 22100°C also showed no evidence of the nionoclinic phase on fracture or ground surfaces. The toughness of the polycrystalline samples was typically 7.7 MPa . m"'. These results indicate that ferroelastic domain switching can occur during fracture and may contribute to toughness. [

Phase and fracture toughness evolution during isothermal annealing of spark plasma sintered zirconia co-doped with Yb, Gd and Nd oxides

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Synthesis and crystallization behavior of 3mol% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP) nanosized powders prepared using a simple co-precipitation process

“…The microcracking toughening mechanism is the second type toughening mechanism, which was proposed by Claussen et al [7] and Evans and Cannon [8]. The third toughening mechanism was proposed by Virkar et al [8][9][10][11]. He proposed that tetragonal ZrO 2 become tougher after stress-induced domain switching.…”

Mechanical properties of ultra-fine grained zirconia ceramics

“…no monoclinic phase at the fracture surface (Table III)). Recently, a number of papers has been devoted to ferroelastic domain switching as a toughening mechanism [32,33]. This involves the stress-induced alignment of the c-axis of the tetragonal phase along the maximum principal stress axis which results in a shape change of a pure shear type.…”