The coherent propagation of an elastic wave in a 2-dimensional continuous elastic medium filled with dislocation arrays, randomly distributed and oriented in space, was studied. This configuration mimicked grain boundaries in polycrystals. Its value lay in evaluating the plastic contributions to the multiple scattering of waves in polycrystals that could superpose on other known scattering processes, such as scattering due to inhomogeneities of the elastic properties among grains. Calculations were performed within a multiple scattering formalism, based upon a derivation of the so-called mass operator in the approximation of weak scattering. It was found that sound attenuation increased when the frequency decreased; a trend which was opposite to the usual behavior. This suggested that dislocations could modify the acoustic properties of materials at low frequency.

Elastic Wave Propagation through a Distribution of Dislocations. A.Maurel, V.Pagneux, D.Boyer, F.Lund: Materials Science and Engineering A, 2005, 400-401, 222-5