Dislocation dynamics prediction of the strength of Al-Cu alloys containing shearable ${\theta }^{\prime \prime }$ precipitates

Abstract

The critical resolved shear stress of an Al 4 wt. \% Cu alloy containing a homogeneous distribution of ${\theta }^{\prime \prime }$ precipitates was determined by means of dislocation dynamics simulations. The size distribution, shape, orientation and volume fraction of the precipitates in the alloy were obtained from transmission electron microscopy observations while the parameters controlling the dislocation/precipitate interactions (elastic mismatch, transformation strains, dislocation mobility and cross-slip probability, etc.) were calculated from atomistic simulations. The precipitates were assumed to be either impenetrable or shearable by the dislocations, the latter characterized by a threshold shear stress that has to be overcome to shear the precipitate. The predictions of the simulations in terms of the critical resolved shear stress and of the dislocation/precipitate interaction mechanisms were in good agreement with the experimental results. It was concluded that the optimum strength of this alloy is attained with a homogeneous distribution of ${\theta }^{\prime \prime }$ precipitates whose average size ($\approx$ 40 nm) is at the transition between precipitate shearing and looping. Overall, the dislocation dynamics strategy presented in this paper is able to provide quantitative predictions of precipitate strengthening in metallic alloys.

References in corpus (5)

• Precipitation during high temperature aging of Al-Cu alloys: a multiscale analysis based on first principles calculations
• Multiscale modelling of the morphology and spatial distribution of θ' precipitates in Al-Cu alloys
• A multidisciplinary approach to study precipitation kinetics and hardening in an Al-4Cu (wt. %) alloy
• Discrete dislocation dynamics simulations of dislocation-${\theta }^{\prime }$ precipitate interaction in Al-Cu alloys
• Basal dislocation/precipitate interactions in Mg-Al alloys: an atomistic investigation

Cited by in corpus (1)

• A generalized line tension model for precipitate strengthening in metallic alloys