Elastic Properties

The measured elastic stiffness and compliance moduli for monoclinic zirconia have been summarized by Chan et al. [30]. The Young’s and shear moduli of this same

Table 4 Polycrystalline Young’s and shear moduli for monoclinic zirconia in GPa (adapted from Chan et al. [30]

20°C

300°C

600°C

800°C

1,000°C

266

256

250

245

239

EReuss

215

216

220

222

214

EHill

241

236

235

234

226

104

99.1

96.8

94.9

92.6

GReuss

83.4

83.2

84.7

85.3

82.4

GHill

93.6

91.1

90.7

90.1

87.5

structure are given in Table 4 and were calculated using the Voigt, Reuss, and Hill approximations. The Voigt and Reuss approximations usually give the upper and lower bounds of these parameters. The maximum errors in these numbers are about 10% for most values, but can increase to greater than 20% for some of the transverse directions in the crystal.

For the monoclinic and tetragonal structures, the bulk modulus hovers around 150— 200 GPa. Cubic zirconia has higher bulk modulus somewhere around 171-288 GPa. The high-pressure phases have values around 224-273 GPa and 254-444 GPa, for the orthorhombic-I and orthorhombic-II phases, respectively.