Atomic-resolution observations of silver segregation in a [111] tilt grain boundary in copper

Alloying a material and hence segregating solutes to grain boundaries is one way to tailor a material to the demands of its application. Direct observation of solute segregation is necessary to understand how the interfacial properties are altered. In this study, we investigate the atomic structure of a high-angle grain boundary both in pure copper and upon silver segregation by aberration-corrected scanning transmission electron microscopy and spectroscopy. We further correlate the experiments to atomistic simulations to quantify the local solute excess and its impact on grain boundary properties. We observe that the grain boundary structure remains intact upon silver segregation and up to five different positions within a structural unit serve as segregation sites. By combining the atomic-resolution observation with atomistic modeling, we are able to quantify the local silver concentration and elucidate the underlying segregation mechanism.

Automated summary

Alloying a material and segregating solutes to grain boundaries is an effective approach to tailor material properties. In this study, we used advanced microscopy and spectroscopy techniques to investigate the atomic structure of a high-angle grain boundary in pure copper and upon silver segregation. Combining experimental observations with atomistic modeling, we were able to quantify the local silver concentration and elucidate the underlying segregation mechanism.