Atomistic simulations of interaction of edge dislocation with twist grain boundaries in Al-effect of temperature and boundary misorientation

Grain boundaries play an important role in characterizing the mechanical behavior of polycrystalline materials, since they can act as sites for absorption or nucleation of dislocations, which are the main carriers of plastic deformation. In view of this, we performed Molecular Dynamics (MD) simulations to study the interaction of edge dislocations with twist grain boundaries. FCC Al was selected as the model material. Simulations were carried out under different temperature conditions (up to 0.9Tm, where Tm is the melting point of Al) on 〈110〉 twist grain boundaries of different misorientation angles. In this way, we were able to quantify the resistance of the grain boundary to dislocation absorption at different temperatures ranging from 10 K to 900 K . Our results reveal that the dislocation absorption resistance varies considerably with the grain boundary misorientation angle, and that the resistance first increases to a maximum before it starts decreasing again as the melting point is achieved. The ramifications of this study towards crystal plasticity finite element modeling are discussed.