Taiki Yanagishima, John Russo, Roel PA Dullens, and Hajime Tanaka

Phys. Rev. Mater. 2021 127 215501

We present a method to locate and characterize grain boundaries in polycrystalline materials from the real-space coordinates of their constituent particles. The method is robust against imperfections such as thermal noise and vacancies. We apply the algorithm to experimentally found real-space coordinates to explicitly measure local misorientations and structure at grain boundaries. We consider particle coordinates obtained from an epitaxially templated colloidal Sigma 17 bicrystal, finding that, even though the bicrystal is predominantly Sigma 17 and face-centered cubic, small volumes of hexagonally closed-packed structure generate a mosaic of grain boundaries, increasing the complexity of the templated grain boundary. We also consider a homogeneously nucleated colloidal polycrystal and apply our method with no prior knowledge of grain boundary structure. Accordingly, we reveal detailed misorientation distributions and grain boundary structures. The method may be applied to any set of coordinates of atoms or particles in a polycrystalline system.

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