Prediction of the strength of aged Al-Cu alloys with non-hybrid and hybrid {1 0 0}Al plates

Abstract

The effect of precipitate hybridization on macroscopic strengthening in aluminum alloys is investigated on the example of Al-Cu alloy using multiscale approach combining molecular dynamics (MD), continuum modeling and discrete dislocation dynamics (DDD). Non-hybrid and hybrid {100}Al plates are considered to involve θ′-phase and θ′-phase in the core and Guinier-Preston zone (GP-like) structure along the broad interfaces, respectively. MD simulations evidence a complex dislocation-precipitate interaction mechanism involving bypassing of both hybrid and non-hybrid {100}Al plates by dislocations at early deformation stages and their shearing by the following dislocations. MD results are used to calibrate a continuum model of dislocation-precipitate interactions in 2D DDD. The shear strength of alloy with hybrid precipitates is found to be 20% higher than that for non-hybrid plates at the same Cu content exceeding 2 wt%.