4th International Congress on 3D Materials Science (3DMS) 2018: New Experimental and Analysis Methods 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
Tuesday 3:50 PM
June 12, 2018
Room: Lille Scene
Location: Kulturværftet (Culture Yard) Conference Center
Session Chair: Robin Woracek, European Spallation Source
Characterization of Crystallographic Interface Character in Additively Manufactured 316L Stainless Steel
: David Rowenhorst1; Lily Nguyen1; Richard Fonda1; 1The US Naval Research Laboratory
Additive Manufacturing (AM) shows great potential for the rapid manufacturing of low volume parts at lower costs. Understanding the microstructural evolution of these materials is of interest since a post-build heat treatment is often used to develop desired properties, thus understanding and predicting the development of these microstructures is essential for understanding the resultant properties of a build. In this presentation, we will show how serial EBSD sections of as-built AM 316, were collected with an automated serial sectioning system, and then present how the distorted EBSD maps were aligned, stacked and reconstructed to make a consistent 3D dataset. We will also discuss data analysis methods for the highly misoriented grains within the structure, and provided the full five parameter grain boundary character distributions for the AM material, and compare the results to those found in our results of traditionally processed 316L.
4:20 PM Invited
Correction of Artificial Density in 3D Reconstructed Micron-Sized Materials Induced by Nonlinear TEM Image Intensity: Jun Yamasaki1; Yuya Ubata1; Kazutoshi Murata2; Kazumi Takahashi3; Shin Inamoto3; Ryusuke Kuwahara4; 1Osaka University; 2National Institute for Physiological Science; 3TORAY research center; 4Okinawa Institute of Science and Technology Graduate University
Quantitative 3D reconstruction by tilt-series tomography needs a data set of projection images in which signals are proportional to integration of the sample structure to each direction. Ideally, image intensity in transmission electron microscopy (TEM) shows exponential attenuation with increasing thickness and thus taking the log gives linear signals. However, in practice, the attenuation deviates from such an exponential curve because of multiple scattering events of the incident electrons especially in micron-thick materials. Using a micron-sized carbon material, we explicitly showed that the deviation induced artificial density in the reconstructed volume. Moreover, we found that the actual attenuation curves were expressed by a function form with a few parameters. Based on total variation regularization for the reconstructed volume, we succeeded in iterative optimizations of the parameter values, which were used for the intensity corrections. As the result, internal structures of a yeast cell appeared more clearly than before the corrections.
Coherent X-ray Diffractive Imaging Simulated by Monte Carlo Ray-tracing: Giovanni Fevola1; Erik Bergbäck Knudsen1; Tiago Ramos1; Gerardina Carbone2; Jens Wenzel Andreasen1; 1Technical University of Denmark; 2MAX IV
Coherent diffractive imaging (CDI) techniques have gained significant momentum in recent years, and most synchrotrons have dedicated beamlines for CDI techniques, with full-field CDI and ptychography (near-field and far-field) among the most commonly applied. Tomographic ptychography combines a large field of view with the capability to image structures in 3D down to about 10 nm in resolution. Simulations of CDI experiments can assist in interpretation of data by regularization of 3D reconstruction to help distinguish signal from noise, or to design experiments that minimize X-ray dose. Several factors are however hampering simulations in a ray-tracing framework, and so far only simplified test-cases have been reported. In this poster, we detail novel enhanced CDI features of the ray-tracing software McXtrace*, and discuss their ability to produce ptychographical datasets. References: * E. Bergbäck Knudsen et al., J. Appl. Crystallogr. 46, 679–696 (2013).
Estimating the Fibre Length Distribution Using the Fibre Endpoint Process: Jan Niedermeyer1; Claudia Redebach1; 1TU Kaiserslautern
The mechanical strength in fibre reinforced polymers is governed by the length and orientation distribution of the fibres. Estimating the fibre length distribution in fibre reinforced polymers from CT data is still a challenge. Image quality usually does not allow a full fibre segmentation. Using Gaussian curvature we can segment the fibre endpoints from a CT image. By interpreting these endpoints as a point process we can then use point process statistics to investigate properties of the underlying fibreprocess. We will investigate methods using point process statistics to estimate the fibre length distribution.
Software Developments for Reduction of High Energy Diffraction Microscopy Data: Hemant Sharma1; Peter Kenesei; Jun-Sang Park; Jonathan Almer; 1Argonne National Laboratory
High Energy Diffraction Microscopy (HEDM) technique is used for non-destructive in-situ characterization of polycrystalline materials during thermo-mechanical treatments. This talk will outline the developments to the MIDAS software for reduction of both Near Field and Far Field HEDM data. We have recently implemented a real-time streaming pipeline for remote data reduction at Sector 1, APS. We will present a comparison of two different approaches for grain tracking during sample evolution: one using diffraction peaks and the other using grain orientations. The applicability of each approach in different cases will be discussed. In addition, a robust methodology for detection of twins in FCC materials will be presented.
Data-driven Modeling of Microstructure Shape Influence on High Cycle Fatigue Life of NiTi Wire: Orion Kafka1; Cheng Yu1; Modesar Shakoor1; Wing Kam Liu1; 1Northwestern University
Nickel-titanium arterial stents and heart valve frames must withstand on the order of one billion heart beats, which results in predominantly axial cyclic loading in the struts of the device. The conventional wire-drawing process induces inclusion break-up, “stringers,” which reduces inclusion axial cross-sectional area while increasing the transverse area. We investigate the influence of final stringer geometry – shape and size of inclusion and voids resulting from inclusion break-up – on fatigue crack incubation life using a fast computational method called crystal plasticity self-consistent clustering analysis. This recently developed method, based data-driven modeling techniques, solves the crystal plasticity constitutive equations within a periodic, 3D representative unit cell. The efficiency of the method allows for parametric study of simplified stringer-like geometries and imaged 3D geometry obtained with serial-sectioning or x-ray tomography. This information can be used for material and manufacturing design, e.g. by providing a design goal that allows for optimization.