The damping response of monocrystalline magnesia which contained 0.004wt%Fe as a major impurity was tested in torsion at temperatures up to near the melting point. The crystal was oriented so that the maximum shear stress would be applied along the (110)<1¯10> primary slip system of the cubic rocksalt structure. Damping data were also collected as a function of the torsional strain amplitude, and were analyzed in terms of a procedure proposed for metallic alloys. The amplitude-dependent decrement of the single crystal at moderate strain amplitudes (10-5 to 10-4) qualitatively followed the predictions of hysteretic dislocation damping theory. By using the results of a Granato-Lucke analysis, the binding energy which controlled dislocation motion was deduced from the damping data.

Mechanistic Analysis of Dislocation Damping in Single-Crystal Magnesia Close to its Melting Point. G.Pezzotti, K.Ota, T.Nishida: Journal of the American Ceramic Society, 1998, 81[12], 3169-72