Description of grain boundary structure and topology in nanocrystalline aluminum using Voronoi analysis and order parameter

Abstract

Abstract Grain boundaries (GB) have a significant impact on mechanical, physical properties and microstructure of polycrystalline materials. Their studies are necessary for designing materials of improved properties. We present molecular dynamics based studies of grain boundary in nanocrystalline aluminum. A Voronoi tessellation based method (Voronoi analysis, VA) and order parameter approach were used for describing structure and topological features in nanocrystalline aluminum. We are portraying new functionality and usefulness of VA combined with order parameter (OP) to picturing structure nature of grain boundary (GB) and its order given in form of configuration entropy. Voronoi analysis unveiled sub-nanoscale topological features contributing to GB which correspond to lattice distortions and liquid-like GB behavior. Grouping of Voronoi cell indices to a crystal lattice distortion group was made together with corresponding to them OP values. Two complementary methods used in this work provide new information and open new possibilities for studying structure and properties of nanomaterials.