6th International Congress on 3D Materials Science (3DMS 2022): 4D Data Analysis I: Plasticity I
Program Organizers: Dorte Juul Jensen, Technical University of Denmark; Marie Charpagne, University of Illinois; Keith Knipling, Naval Research Laboratory; Klaus-Dieter Liss, University of Wollongong; Matthew Miller, Cornell University; David Rowenhorst, Naval Research Laboratory
Monday 9:30 AM
June 27, 2022
Room: Capitol B
Location: Hyatt Regency Washington on Capitol Hill
Session Chair: Anter El-Azab, Purdue University
9:30 AM Invited
In Situ High Energy X-ray Diffraction Study of the Elastoplastic Transition in a Polycrystalline Metastable β Ti Alloy: Jishnu Bhattacharyya; Darren Pagan; Gergely Farkas; Kristián Máthis; Vahid Tari; S. Nair1; Ricardo Lebensohn; Anthony Rollett; Sean Agnew2; 1Cornell High Energy Synchrotron Source; 2University of Virginia
The elastic strain tensor and orientation of individual grains within a metastable β-Ti alloy were tracked throughout the elastoplastic transition, using in-situ HEXD. A simple strategy to obtain the single-crystal elastic constants is demonstrated. The elastic anisotropy and intergranular interactions have a strong impact on the constitutive response of the aggregate. Full-field crystal plasticity simulations and single-crystal line profile analysis reveal that pencil glide is operative, and there is no preference for dislocations to reside on a particular glide plane. A new method to estimate the geometrically necessary dislocation (GND) density from rocking curves is introduced revealing a lack of correlation between the GND density and grain-level stress or higher hardening response. Finally, rotations of the grain-level stress tensor are revealed to be an order of magnitude larger than the lattice reorientation. These results provide new perspectives through which to contemplate the question of “hot-spots” responsible for failure.
10:00 AM
Application of a Laboratory-Based Multimodal X-ray Tomography to Study in 3D Correlations Between Grain Structure and Local Strain Distribution: Masakazu Kobayashi1; Yubin Zhang2; Jun Sun3; Jette Oddershede3; Dorte Jensen2; Runguang Li2; Hiromi Miura1; 1Toyohashi University of Technology; 2Technical University of Denmark; 3Xnovo Technology ApS
Metals are known to deform inhomogeneously. In this work multimodal X-ray tomography, i.e. attenuation tomography (ACT) and diffraction contrast tomography (LabDCT), was applied to study plastic deformation of a fully recrystallized Al-4mass%Cu alloy in 3D. Several correlations were examined between the 3D grain structure visualized by LabDCT and the local plastic strain distribution measured by a microstructural feature tracking (MFT) method based on ACT images before and after tensile deformation. The advantage and potentials of non-destructive 3D characterization of plastic deformation by the combination of laboratory X-ray ACT and MFT are discussed, the spatial resolution of the strain distribution measurements are quantified, and the observed microstructure-strain correlations are presented.
10:20 AM
Observing Bulk Plasticity in Ti-7Al by Topotomography: Patrick Callahan1; Jean-Charles Stinville2; Henry Proudhon3; Mclean Echlin4; Wolfgang Ludwig5; Tresa Pollock4; 1Us Naval Research Laboratory; 2University of Illinois Urbana-Champagne; 3MINES Paris; 4University of California Santa Barbara; 5University of Lyon
The interaction of defects with the microstructure in metallic materials often governs their mechanical properties. In this study, the plastic localization in a polycrystalline Ti-7Al sample was observed at the surface using high-resolution digital image correlation (HR-DIC) in an SEM and in the bulk using x-ray topotomography at ESRF. The full 3D microstructure was determined using diffraction contrast tomography. A number of grains of interest were chosen from the 3D microstructure and studied by topotomography and several steps of increasing strain. Highly localized regions of contrast were observed in the x-ray topographs. The contrast is due to plastic localization, and so it enabled us to identify the bulk plasticity. From these observations, slip transmission in the bulk could be studied in terms of the configuration of the polycrystalline microstructure, and compared to the observations at the surface as determined from the HR-DIC measurements.
10:40 AM
Large Deformations of Metal Foams: Dynamic CT Results, Simulations, and Modeling: Sebastian Rief1; Martina Hümbert1; Andreas Grießer1; Erik Glatt1; Wesley De Boever2; 1Math2Market GmbH; 2TESCAN XRE
Metal foams are used in a wide range of applications, such as lightweight materials. As an integral part of a structure, the mechanical characteristics of metal foams and their response to external load need to be well understood. To gain greater insights, we use lab-based dynamic CT (by TESCAN) to visualize the uninterrupted compression of aluminum metal foams. Mechanical simulations of the same samples, carried out with the GeoDict software, are then compared to those results.The dynamic CT reveals different modes of deformation, like buckling or bending of struts, and collapsing of cells. Moreover, the displacement and deformation of pores are analyzed on the scanned images imported into the software. Two samples from the same foam are tested, analyzed, and simulated. The comparisons show very good agreement in the stress-strain curves and also in the observed geometrical deformations.