Interaction between a dislocation and nanotwin-hcp lamella in Ni-based concentrated alloys from atomistic simulations

S Hayakawa and HX Xu, SCRIPTA MATERIALIA, 218, 114810 (2022).

DOI: 10.1016/j.scriptamat.2022.114810

We investigate the fundamental interaction between a dislocation and nanotwin-hexagonal close-packed (hcp) lamella in Ni-based concentrated alloys using molecular dynamics simulations. We identify two types of interaction modes that have different contributions to the ductility: the lamella either transmits or absorbs the dislocation. Furthermore, the dominant interaction mode changes with an increase in the interaction's critical stress, which exhibits a strong dependence on a material parameter related to the stacking fault energy. The combination of the dominant mode and critical stress dependences could lead to the simultaneous increase in the strength and ductility with decreasing temperature in NiCoCr. Additionally, it is found the type of interaction mode to occur is influenced by the hcp lamella thickness, which could further enhance the ductility, together with the unique mechanism of the dislocation absorption. The obtained insights would be useful for the fundamental understanding of the intriguing properties of Ni-based concentrated alloys.

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