Atomistic modeling of plastic deformation in B2-FeAl/Al nanolayered composites

In this work, the deformation response of the B2-FeAl/Al intermetallic composites, as a model material system for nanolayered composites comprised of intermetallic interfaces, has been explored. We use atomistic simulations to study the deformation mechanisms and the interface misfit dislocation structure of B2-FeAl/Al nanolayered composites. It is shown that two sets of dislocations are contained in the interface misfit dislocation network and are correlated with the initial dislocation nucleation from the interfaces. The effects of layer thickness on the uniaxial deformation response of the B2-FeAl/Al multilayers are investigated. We observed that under compressive loading the smaller proportion of the FeAl layers leads to the lower overall flow stress. Under tensile loading, the void formation mechanism is investigated, suggesting the interface structure and the dislocation activities in the FeAl layers playing a significant role to trigger the strain localization which leads to void nucleation commencing at the interface. It is also found that the deformation behavior in the weak Fe/Cu interface behaves substantially different than that of the strong FeAl/Al interface. The atomistic modeling study of the nanolayered composites here underpinned the mechanical response of strong intermetallic interface material systems. There is no void nucleation during the entire plastic deformations in the Fe/Cu simulations, which is attributed to much higher dislocation density, more slip systems activated, and relative uniformly distributed dislocation traces in the Fe phase of the Fe/Cu multilayers.

Automated summary

This research explores the deformation mechanisms and interface misfit dislocation structures of B2-FeAl/Al nanolayered composites through atomistic simulations. It is found that there are two sets of dislocations in the interface misfit dislocation network, and the influence of layer thickness on uniaxial deformation response is investigated. The study also reveals differences in deformation behavior between weak Fe/Cu and strong FeAl/Al interfaces, with the latter triggering strain localization and void formation.