Phonon Scattering by Impurity Atmospheres Surrounding Dislocations. III. Combined Mass and Distortion Scattering

Abstract

The inhomogeneous distribution of solute atoms in the presence of the strain field of dislocations causes additional phonon scattering in alloys. This nonuniformity results from the size difference between solute and solvent atoms. A previous theory considered the source of the scattering to be the mass difference between solute and solvent atoms. It is now shown that the size difference which causes the inhomogeneous distribution is, at the same time, an important additional source of scattering, which will always reinforce the anharmonic scattering of the strain field. The case of copper‐aluminum alloys is considered because of recent measurements made on this system. At higher temperatures (shorter phonon wavelengths) scattering by the individual solute atoms becomes relatively more important.