A generalized three-dimensional (3D) vertex dynamics model for simulating grain growth is presented. In this approach, grain boundaries (GB) are triangulated and the microstructural evolution is driven by the minimization of the GB energy. The generalized model includes misorientation and inclination dependent GB energies and mobilities. The model systems considered are SrTiO3 ceramics.The paper describes the derivation of the equations for the dynamics and the algorithm for handling topological changes in the GB network in detail. For isotropic grain growth, the numerical results for the volume change rate of embedded grains are in excellent agreement with the MacPherson–Srolovitz relation which can be interpreted as the 3D analogue of the von Neumann–Mullins law. The inclination dependent GB energy yields a torque contribution on the GB shape. This is illustrated by means of 2D cross-sections of structures modelled with and without inclination dependence showing rather flat GBs for the energetically favourable GB inclinations.
The three-dimensional grain boundary network of sintered bulk strontium titanate is reconstructed using X-ray diffraction contrast tomography, a non-destructive technique for determining the grain shape and crystallographic orientation in polycrystals that is ideally suited for detailed studies of microstructure evolution. We present the first microstructure reconstruction of a perovskite comprising 849 grains and detailed interface orientation evaluations of individual grains. Comparison of structural and topological quantities to metallographic investigations and statistical grain models demonstrates the method's validity and applicability
Recently, techniques for the acquisition of three-dimensional tomographic and four-dimensional time-resolved data sets have emerged, allowing for the analysis of mm 3 volumes of material with nm-scale resolution. The ability to merge multi-modal data sets acquired via multiple techniques for the quantitative analysis of structure, chemistry and phase information is still a significant challenge. Large three-dimensional data sets have been acquired by time-resolved diffraction contrast tomography (DCT) and a new TriBeam tomography technique with high spatial resolution to address grain growth in strontium titanate. A methodology for combining three-dimensional tomographic data has been developed. Algorithms for the alignment of orientation reference frames, unification of sampling grids and automated grain matching have been integrated, and the resulting merged data set permits the simultaneous analysis of all tomographic data on a voxel-by-voxel and grain-by-grain basis. Quantitative analysis of merged data sets collected using DCT and TriBeam tomography shows that the spatial resolution of the DCT technique is limited near grain boundaries and the sample edge, resolving grains down to 10 mm diameter for the reconstruction method used. While the TriBeam technique allows for higher-resolution analysis of boundary plane location, it is a destructive tomography approach and can only be employed at the conclusion of a four-dimensional experiment
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.