A theory of dislocation/solute-atom interactions in solid solutions was developed which permitted the calculation of the non-linear dislocation strain-amplitude dependent internal friction. The model accounted for various types of dislocation/solute-atom interaction. One case was where solute atoms distributed on the dislocation glide plane interacted with the dislocation core and were short-range obstacles to dislocation motion. In another case, solute atoms which were situated away from the dislocation glide plane created relatively weak long-range elastic stress fields which again impeded dislocation motion. It was assumed that dislocations moved in a 2-component system of obstacles which differed with respect to the thermodynamics of dislocation/point-defect interaction. That is, dislocations overcame short-range obstacles under the combined efforts of the applied stress and thermal energy, whereas relatively weak long-range obstacles were surmounted athermally. The model predicted a complicated multi-stage behavior of the non-linear internal friction, in the strain-amplitude temperature solute-concentration domain, which was in excellent agreement with experimental data.

Theory of Dislocation-Solute Atom Interactions in Solid Solutions and Related Non-Linear Anelasticity. G.Gremaud, S.Kustov: Physical Review B, 1999, 60[13], 9353-64