4th International Congress on 3D Materials Science (3DMS) 2018: Measuring and Predicting Grain Shapes, Sizes, Crystallography, and Spatial Distributions II
Program Organizers: Hugh Simons, Denmark Technical University; Henning Poulsen, Denmark Technical University; David Rowenhorst, Naval Research Laboratory; Peter Voorhees, Northwestern University; Satoshi Hata, Kyushu Univ; McLean Echlin, UC Santa Barbara
Wednesday 10:20 AM
June 13, 2018
Room: Lille Scene
Location: KulturvŠrftet (Culture Yard) Conference Center
Session Chair: David Rowenhorst, Naval Research Laboratory
10:20 AM Invited
Dark-field X-ray Microscopy in the Shadow of Biominerals: Phil Cook1; Jean-Pierre Cuif2; Yannicke Dauphin2; Carsten Detlefs1; Elise Dufour3; Anders Jakobsen4; Mustafacan Kutsal1; Henning Poulsen4; Vanessa Schoeppler5; Hugh Simons4; Can Yildirim1; Igor Zlotnikov5; 1ESRF; 2MusÚum nationale d’Histoire naturelle; 3UMR 7209 CNRS/MNHN; 4Danish Technical University; 5BCUBE
We have examined biominerals using dark-field x-ray microscopy and will illustrate new perspectives on their microscale crystalline properties. Dark-field x-ray microscopy allows multiscale in situ diffraction topography imaging of biomineral fibres (~100 Ám), bundles (~10 Ám), and their component prismatic crystalline units (~1 Ám) using Bragg diffracted beams with a 100 nm real space resolution, 0.001░ angular resolution, and strain resolution of 10^-5.We describe several examples studied at the recently commissioned instrument at ESRF ID06. In fish otoliths, we present bulk analyses of crystalline bundles, revealing the relative orientation relations of the prismatic crystals as well as internal variations in orientation and strain. In a Pinctada shell prism we show that, while it is quasi-monocrystalline, there are variations in crystallite orientation on the order of 10^-3 degrees along with strain variations on the order of 10^-5. We investigate the relation of habits of biomineral crystals and internal strains.
3D TEM Characterization of Polycrystalline Metals: Xiaoxu Huang1; Qiongyao He2; Zongqiang Feng2; Guilin Wu2; S°ren Schmidt1; 1Technical University of Denmark; 2Chongqing University
Mechanical properties of polycrystalline metals are determined by their microstructural, crystallographic and chemical parameters. Recent development of electron tomography, 3D orientation mapping and 3D atom probe has enabled precise characterizations of a diversity of 3D microstructural, crystallographic and chemical information from a variety of materials, which offers new opportunities for 3D materials science of polycrystalline metals at nanoscale. In this presentation, the progresses in developing TEM-based 3D orientation mapping and dislocation tomography techniques are demonstrated by showing examples obtained in polycrystalline metals. New challenges will be disccused with respect to the development of sample stage and reconstruction software for a full and precise 3D characterization of microstructural and crystallographic parameters.
Finite Element Simulation of Grain Growth with an Arbitrary Grain Boundary Energy: Erdem Eren1; Jeremy Mason1; 1University of California, Davis
Three-dimensional microstructure reconstructions and grain boundary energy reconstructions provide input and validation data that could dramatically improve simulations of microstructure evolution. Unfortunately, there are few simulations that can make full use of this data in the literature. We have developed a finite element simulation that (1) uses a volumetric mesh to allow the eventual inclusion of arbitrary material physics, (2) significantly expands the set of allowed topological transitions to allow for general grain boundary network dynamics, and (3) proposes an energy dissipation criterion to select a topological transition in a system with arbitrary grain boundary energy. This talk will mainly focus on the second and third points, since they seem to be novel in the literature. The resulting finite element code (based on SCOREC by the Rensselaer Polytechnic Institute) is expected to improve the ability of simulations to reproduce recently available experimental observations of microstructure evolution in three dimensions.
Missing Information and Data Fidelity in Digital Microstructure Acquisition: Mo Li1; 1Georgia Institute of Technology
Microstructure is one of the pillars supporting the structure-property relations in materials science and engineering. Its digitized format, the digital microstructure, plays an increasingly vital role in materials genome, new architecture design and advanced manufacturing of functional materials. Despite the efforts in the past decade, one basic issue facing digital acquisition of microstructures is left untouched, that is, how much information is missing in the first step of data gathering and processing. Here using a polycrystal model and new microstructure characterization methods, we show quantitatively the missing information and related data fidelity. The lost microstructural data could become significant depending on the experimental resolution and the nature of the microstructures. We also discuss the uncertainties and deviations in the predicted material properties caused by the lost microstructural information.
Investigation of the 3D Microstructure of Additively Manufactured 316L Stainless Steel: Lily Nguyen1; David Rowenhorst2; Richard Fonda2; 1National Research Council / Naval Research Laboratory; 2Naval Research Laboratory
Additive manufacturing (AM) is a layer-by-layer processing technique that results in a highly complex microstructure. Due to the inherent 3D nature of this process, 2D observations provide an incomplete understanding of how its microstructure forms. This presentation will describe how a fully automated serial sectioning system was developed to collect a large volume of AM 316L using traditional SEM imaging and EBSD data at a high resolution. We will also present an initial analysis that shows the scan strategies, including build direction and scanning direction, can affect the crystallographic texture and morphology of the grains. We will present our results using spatial and texture analysis to examine the relationship between microstructure and AM processing.