Cross-slip mechanisms of ⟨111⟩ screw superdislocations in FeAl

The evolution of the core structure and the cross-slip behavior of a screw [111] superdislocation are investigated by molecular dynamics simulations at external pressures and shear stresses in FeAl with the B2 structure. The result reveals that the transformation between different core configurations generally determines the cross-slip behavior of a dissociated superdislocation after the application of pressures and shear stresses. In terms of the core transformation, two novel cross-slip mechanisms are provided for a dissociated superdislocation. Furthermore, a numerical calculation method is proposed to quantitatively assess the critical shear stress of the core transformation and cross-slip at distinct pressures, the result of which shows a great agreement with the simulation results. In addition, the influence of applied stresses on the competition between the glide and cross-slip behaviors of a dissociated superdislocation is discussed. It shows that the numerical calculation can advance the understanding for the dependence of the core configuration and the motion of dissociated superdislocations on applied pressures and shear stresses.

Automated summary

The study investigates the evolution of core structure and cross-slip behavior of a screw [111] superdislocation in FeAl through molecular dynamics simulations. It reveals that the transformation of core configurations determines the cross-slip behavior, proposing two new cross-slip mechanisms. A numerical calculation method is introduced to quantitatively assess the critical shear stress of core transformation and cross-slip under different pressures, showing good agreement with simulation results. The influence of applied stresses on the competition between glide and cross-slip behaviors of a dissociated superdislocation is also discussed, advancing the understanding of core configuration dependence on external pressures and shear stresses.