Prediction of shear strength of cluster-strengthened aluminum with multi-scale approach describing transition from cutting to bypass of precipitates by dislocations

•Molecular dynamics study of interaction of edge dislocation with 1-4 nm copper clusters in aluminum is carried out.•Main mechanism of overcoming of 1-1.2 nm copper clusters is its cutting by dislocation.•Main mechanism of overcoming of 1.4-4 nm copper clusters is its bypass by Orowan mechanism.•Model of dislocation motion in aluminum with copper clusters is developed with accounting of precipitate cutting/bypass.•Parameters of precipitate cutting/bypass model are fitted to MD data with the Bayesian algorithm.•Model of dislocation motion with precipitate cutting/bypass is implemented into 2D discrete-dislocation dynamics.•DDD predicts flow stress of alloy close to experimentally observed.•Alloy with cluster demonstrates substantially lower tendency to plastic localization in comparison with classically aged ones. We investigate the deformation of aluminum alloy containing copper in the form of fine Al-Cu clusters 1–4 nm in diameter with multiscale approach. A part of these precipitates (clusters of 1–2 nm in diameter) reproduce that were experimentally obtained by (Sun et al., 2019) by cyclic dynamic loading of aluminum alloy. At the first stage, molecular dynamics (MD) reveals that main mechanism of interaction of dislocation with the copper-containing cluster are cutting of precipitate for 1 nm cluster and bypass by Orowan mechanism for clusters with diameters above 1.4 nm. Single events of climb are observed in MD, frequency of which increases with a temperature raise. The stresses level realized for the climb mechanism practically do not differ from that of the basic mechanism for the considered inclusion diameters. Also, the results of MD simulations show that the strength of the cluster depends on the presence of enough number of copper atoms on the slip plane of dislocation and does not directly depend on the concentration of copper when it varies in the range of 20–100% inside the precipitate. Reduction of copper concentration below 20% decreases the precipitate resistance, and the system behavior converges to the case of pure aluminum at 0%. These results are supported by MD calculations of generalized stacking fault energy, which demonstrate a weak dependence of unstable stacking fault energy on copper concentration in the range of 30–70%. A continuum model of dislocation motion in aluminum containing the copper-containing cluster is proposed, which considers the kinetics of dislocation-precipitate interaction and accounts for the transition from