The Young's and shear moduli of polycrystalline monoclinic hafnium oxide were determined by the sonic resonance method at room temperature as a function of volume fraction porosity. The Spriggs equation empirically described the data and the zero porosity moduli as 283.6 GN/mZ and 109.2 GN/m2 for Young's and shear moduli, respectively. The Debye temperature calculated from the elastic constants was 484°K. Several specimens had anomalously low moduli values, attributed to microcracking. Grain size and internal friction measurements showed that the microcracking occurred in specimens with grain sizes >2 to 3 pm and was characterized by high internal friction.

Die Elastizitäts‐ und Schubmoduln von polykristallinem monoklinen HfOg werden mit der Schallresonanzmethode bei Raumtemp; als Funktion der Porosität bestimmt.