Atomic-Scale Studies of Defect Interactions with Homo- and Heterophase Interfaces

Abstract

Interfaces are planar metastable defects with singular features capable of controlling diverse material properties, including mechanical response and the microstructure evolution in materials under irradiation. This ability of interfaces to dictate the material response resides inherently in their atomic structure, which controls the interactions of dislocations as well as point and defect clusters with the interface. We recently showed how dislocations nucleated from defect clusters interact with a heterophase interface in Cu–Nb layered composites. We also showed how the ability of the interface to absorb vacancy clusters depends on the atomic structure at the interface. Herein, we elaborate on the effect of the atomic structure on the ability of the interface to absorb dislocations as well as vacancy and self-interstitial defect clusters. We study a physical-vapor-deposited Kurdjumov–Sachs orientation in a Cu–Nb interface and an asymmetric $\Sigma$11 grain boundary in pure Cu. On the one hand, the manner in which dislocations react with the interface depends on the misfit dislocation arrangement, which substantially differs between these two cases. On the other hand, vacancy and self-interstitial clusters are absorbed similarly upon interaction with both structures.