A dislocation model for strain burst in cyclic creep of substitutional solid solutions

Abstract

A new dislocation model for strain bursts in cyclic creep of substitutional solid solutions is proposed on basis of the breakdown of dislocation cell walls and the interactions between dislocations and solute atoms. This theoretical model gives quantitative expressions for the following four parameters: the threshold stress for strain bursts; the amplitude of strain bursts; the critical concentration of solute atoms required for the Occurrence of strain bursts; the critical temperature for the disappearance of strain bursts. The theoretical predictions are verified by experimental results on cyclic creep of Al-Mg solid solution alloys. Finally, the contribution of obstacle dislocations within cell walls and mobile dislocations in cell interiors to creep deformation during strain bursts is also discussed