Enhanced strain rate sensitivity due to platelet linear complexions in Al-Cu

TL;DR

This study uses atomistic simulations to show that platelet linear complexions in Al-Cu significantly increase strain rate sensitivity due to dislocation climb mechanisms, impacting plasticity.

Contribution

It reveals the enhanced strain rate sensitivity caused by platelet linear complexions in Al-Cu, a novel insight into their impact on plastic deformation.

Findings

Strain rate sensitivity is up to five times higher in platelet complexions.

Dislocation climb into precipitates introduces a time-dependent barrier.

Enhanced sensitivity affects plasticity behavior.

Abstract

Platelet array linear complexions have been predicted in Al-Cu, with notable features being dislocation faceting and climb into the precipitate, both of which should impact plasticity. In this study, we examine the strain rate dependence of strength for platelet linear complexions using atomistic simulations, with classical precipitate strengthening through particle cutting and particle bowing used as baseline comparisons. Dislocation segments with edge character must climb down from the platelet structures prior to the commencement of glide, introducing a significant time-dependent barrier to plastic deformation. Consequently, the strain rate sensitivity of strength for the platelet linear complexions system was found to be up to five times higher than that of classical precipitation strengthening mechanisms.