A full rate-dependent constitutive theory for dynamic strain-aging was developed based upon two key ideas. The first idea was that both solute strengthening and forest strengthening must exist and must exhibit aging phenomena. The second idea was that a single physical aging mechanism, cross-core diffusion within a dislocation core, controlled the aging of both the solute and forest strengthening mechanisms. All the material parameters in the model, apart from forest dislocation density evolution parameters, were derivable from atomistic-scale studies so that the theory contained essentially no adjustable parameters. The model predicted the steady-state stress/strain/strain-rate/temperature/concentration dependent material response for a variety of Al–Mg alloys, including negative strain-rate sensitivity, in qualitative and quantitative agreement with available experiments. The model also revealed the origin of non-additivity of solute and forest strengthening, and explained observed non-standard transient stress behaviour in strain-rate jump tests.

Solute Strengthening of Both Mobile and Forest Dislocations - the Origin of Dynamic Strain Aging in FCC Metals. M.A.Soare, W.A.Curtin: Acta Materialia, 2008, 56[15], 4046-61