Single‐Crystal Elastic Constants of Yttria‐Stabilized Zirconia in the Range 20° to 700°C

Elastic constants of single crystals of yttria‐stabilized zirconia were determined through the temperature range 20° to 700°C. Crystals containing 8.1, 11.1,12.1, 15.5, and 17.9 mol% Y 2 0 3 were measured. The elastic constant C 11 was found to decrease and C 12 and C 44 to increase with increasing Y 2 O 3 content; this appears to be due to decreasing coulombic interaction as Y 3+ replaces Zr 4+ . Except for the 8.1 mol% Y 2 O 3 crystal, the conventional elastic constants all showed normal monotonic decreases with increasing temperature. In the case of the 8.1 mol% Y 2 O 3 crystal, measurements as a function of temperature were not reproducible, and it is likely that this composition at room temperature is below the composition limit of thermodynamic stability of the cubic fluorite phase.