Advanced Characterization Techniques for Quantifying and Modeling Deformation: Session IV
Sponsored by: TMS Extraction and Processing Division, TMS Materials Processing and Manufacturing Division, TMS Structural Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Materials Characterization Committee
Program Organizers: Rodney McCabe, Los Alamos National Laboratory; Marko Knezevic, University of New Hampshire; Irene Beyerlein, University of California, Santa Barbara; Wolfgang Pantleon, Technical University of Denmark; C. Tasan, Massachusetts Institute of Technology; Arul Kumar Mariyappan, Los Alamos National Laboratory; Olivia Underwood Jackson, Sandia National Laboratories
Tuesday 2:00 PM
March 16, 2021
Room: RM 13
Location: TMS2021 Virtual
2:00 PM Invited
A Framework for Quantitative Measurement of Plastic Deformation in Relation to 3D Microstructure: J.C. Stinville1; M. A. Charpagne1; A. Cervellon1; J. Hestroffer1; M. P. Echlin1; V. Valle2; D. Texier3; I.J. Beyerlein1; T. M. Pollock1; 1University of California, Santa Barbara; 2Institut P' - UPR 3346, CNRS - Université de Poitiers - ENSMA; 3Institut Clément Ader - UMR CNRS 5312
To develop predictive model for monotonic and cyclic loading of polycrystalline metallic alloys, there is a need for quantitative experimental assessment of plastic deformation at the scale of the microstructure over 3D representative field of view. Moreover frameworks for direct comparison of experimental measurements and numerical simulation results need to be established. New developments in High-Resolution Digital Image Correlation (HR-DIC) and 3D tomography provide unique opportunities to capture large datasets that detail elastic and plastic deformation in relation to 3D microstructure. Examples are given during cyclic and monotonic deformation of 718 nickel-based superalloys for direct comparison with 3D numerical simulations. The effects of 3D grain and precipitate structures on plastic localization are detailed and their impact on nickel based-superalloy fatigue modeling is explained.
2:30 PM
Characterization and Modelling of Twin Evolution and Cyclic Deformation in Magnesium Alloys by High Energy X-ray Diffraction Microscopy: Duncan Greeley1; Mohammadreza Yaghoobi1; Darren Pagan2; Veera Sundararaghavan1; John Allison1; 1University of Michigan; 2Cornell High Energy Synchrotron Source
Twinning and detwinning play an important role in deformation evolution during low-cycle fatigue of magnesium alloys. Understanding both the influence of microstructure and texture on twin evolution as well as the mechanistic impact of the twin-detwin process on local micromechanical states are necessary for accurately predicting fatigue behavior. Cyclic deformation of Mg-2.4wt.%Nd was analyzed in this study through in-situ far-field and near-field High Energy X-Ray Diffraction Microscopy (HEDM) at the Cornell High Energy Synchrotron Source (CHESS). Grain-scale twin nucleation, growth, and detwinning were tracked using far-field HEDM and were correlated to the evolution of grain elastic strain and orientation during single fully-reversed, displacement controlled loading cycles. The impact of twin activity on parent grain and grain-neighborhood deformation was investigated, and deformation in the 3D near-field HEDM microstructure was simulated with the PRISMS-Plasticity crystal plasticity finite element software. The dataset from this study is published in the Materials Commons data repository.
2:50 PM
Elastoplastic Transition in a Metastable β-titanium Alloy, Timetal 18 by In-situ High Energy X-ray Diffraction: Jishnu Bhattacharyya1; Sriramya Nair2; Darren Pagan3; Vahid Tari4; Ricardo Lebensohn5; Anthony Rollett6; Sean Agnew1; 1University of Virginia; 2Cornell University; 3Cornell High Energy Synchrotron Source, Cornell University; 4Eaton Corporate Research and Technology; 5Los Alamos National Laboratory; 6Carnegie Mellon University
High energy X-ray diffraction is used to measure evolutions of the complete elastic strain tensor and the crystallographic orientation of individual grains of a metastable β-Ti alloy, Timetal-18, in solutionized and quenched state. Using these data, a strategy to obtain the single crystal elastic constants (SEC) is demonstrated. The experimental data are compared with the predictions of the parallelized elasto-viscoplastic Micromechanical Analysis of Stress-Strain Inhomogeneities with fast Fourier transform (MASSIF) code instantiated with a measured 3D microstructure. Examination of the individual grain responses revealed “strain softening” in a subset of grains which we hypothesize is due to distinct initial intra-granular substructure. Finally, the rotation of the grain-level stress state (e.g. the rotations of the eigenvectors of the principal stresses), which has long been theorized to occur during the elastoplastic transition, is experimentally verified and shown to be much larger than the crystallographic reorientation of the lattice due to slip.
3:10 PM
A Strain Gradient Crystal Plasticity Constitutive Model for Hexagonal Close-packed Polycrystals: Omid Sedaghat1; Hamidreza Abdolvand1; 1Western University
A strain gradient crystal plasticity finite element (CPFE) model is developed to study deformation mechanisms of hexagonal close-packed polycrystals. The development of internal lattice strains from the model are compared to previously published data for a series of in-situ neutron diffraction experiments conducted on α-zirconium specimens. This is followed by importing the “as-measured” grain maps of two different specimens undergoing uniaxial tensile loading into the model. While deformation twinning is active in the first specimen, plastic deformation in the second specimen is only accommodated by slip. The calculated elastic lattice rotation, stress and geometrically necessary dislocation (GND) densities are compared to those measured using high angular resolution electron back scatter diffraction (HR-EBSD) technique. Furthermore, two different approaches for determining GND densities in the strain gradient CPFE model are compared. Finally, the capability of the model to capture the slip bands is investigated.
3:30 PM
Estimating Stress on the Microstructural Length Scale Using the Measured Strain Field: Benjamin Cameron1; Cem Tasan1; 1Massachusetts Institute of Technology
A significant challenge in metallurgy is estimating the heterogeneous stress distribution at a microstructural length scale. Recently a new approach has been developed to compute the stress field from a measured strain field through solving a linear hyperbolic set of partial differential equations. We show how this approach can be applied to in-situ deformation experiments in order to accurately compute the stress. Specifically, in-situ tensile experiments are conducted in an electron microscope on samples of electrodeposited copper with columnar grains. This enables a number of assumptions such as transverse isotropy to be made. The strain field is measured by tracking points and the stress is computed by solving the equations mentioned above. Using these results, we analyze the variance in the stress-strain relationship and relate it to the local microstructural geometry. This gives insight into which microstructural geometries have desirable mechanical properties.
3:50 PM Invited
FFT-based Modeling of Strain Localization in Nano-metallic Laminates: Miroslav Zecevic1; Ricardo Lebensohn1; Thomas Nizolek1; Rodney McCabe1; Laurent Capolungo1; 1Los Alamos National Laboratory
Recent experiments have shown that nano-metallic laminates (NMLs) fail through shear banding for compression perpendicular to layers and by kink banding for layer parallel compression. In this work, we develop a large strain FFT-based crystal plasticity model to provide insight into the effects of interface geometry and loading conditions on these failure mechanisms. Single crystal Cu and Nb laminates with experimentally observed crystallographic orientation relationships are simulated with interfaces represented by sinusoidal waves of different amplitude and phase angle. We show relationships between the propensity for shear and kink band formation with the crystallographic orientations, sine wave characteristics, and loading conditions.
4:20 PM
Dynamic Recovery Observed in Distinct Grains Within A Polycrystalline Nickel-based Superalloy During Cyclic High Temperature Loading via High Energy X-ray Diffraction Microscopy: Sven Gustafson1; Darren Pagan2; Paul Shade3; Michael Sangid1; 1Purdue University; 2Cornell High Energy Synchrotron Source; 3Air Force Research Laboratory
Predictions of thermo-mechanical deformation and associated residual stress states are limited by the sparseness of in-situ, 3D grain and sub-grain scale data to investigate the underpinning mechanisms. To further this investigation, elastic micromechanical fields are tracked for a nickel-based superalloy polycrystal via high energy X-ray diffraction microscopy (HEDM) and corresponding intragranular deformation metrics are determined with peak broadening analysis during cyclic high temperature loading. An LSHR sample with over 250 grains was subjected to uniaxial tension and held under fixed displacement while thermally cycling between 460°C and 770°C, with intermittent HEDM characterization to study the grain average response to thermo-mechanical deformation. Elevated temperatures were found to allow for heterogeneous amounts of recovery amongst distinct grains within the sampled region, indicating complex grain interactions; the extent of recovery was greater at higher temperatures.
4:40 PM
Statistical Assessment of Strain Localization in Inconel 718 Informed by Digital Image Correlation Coupled with 3D EBSD: Marie Charpagne1; J.C. Stinville1; Andrew Polonsky1; McLean Echlin1; Valery Valle2; Tresa Pollock1; 1University of California, Santa Barbara; 2P' Institute ENSMA Poitiers
Understanding strain localization in polycrystalline metallic materials is of utmost interest for prediction of mechanical properties such as fatigue. In this study strain localization processes in relation to the 3D microstructure are investigated, in the structural alloy Inconel 718. High Resolution Digital Image Correlation strain measurements are accurately spatially merged with TriBeam 3D Electron backscatter diffraction data in order to determine the relationship between the grain structure and slip localization. Multi-modal data merging and advanced analysis algorithms are employed to statistically study plastic localization events as a function of the 3D microstructure, over large microstructural regions. Quantitative correlations between the amplitude of localization, activated slip systems and locations of thousands of individual slip bands and microstructure features (grain boundaries, annealing twin boundaries, triple junctions, quadruple points) will be discussed. Slip localization locations and active slip systems will be discussed in regards to theoretical predictions.
5:00 PM
Analysis of Slip Transfer in Ti-5al-2.5 (Wt. %) at Two Temperatures in Comparison to Pure Aluminum: Chelsea Edge1; Thomas Bieler1; 1Michigan State University
Understanding the deformation mechanisms present near grain boundaries in polycrystalline hexagonal alloys will aid in improving modeling methods. Ti-5Al-2.5Sn samples were tensile tested at 296K and 728K, and slip behavior was assessed near grain boundaries. From the EBSD measurements of grain orientations, various metrics related to the slip systems, traces, residual Burgers vectors, and grain boundary misorientation were computed for boundaries showing evidence of slip transfer and boundaries showing no evidence of slip transfer. This work is compared to a similar study of an Aluminum oligo-crystal to aid in understanding the differences in slip behavior near grain boundaries in HCP and FCC crystal structures. Slip transfer in Ti525 was generally observed in less geometrically compatible conditions than Al, and slip transfer occurs at high misorientation angles in Ti-5Al-2.5Sn much more frequently than in Al.
5:20 PM
Orientation, Pattern Center Refinement and Deformation State Extraction through Global Optimization Algorithms: Chaoyi Zhu1; Christian Kurniawan1; Marcus Ochsendorf1; Marc De Graef1; 1Carnegie Mellon University
Global optimization algorithms have been adopted to refine orientation and pattern center for electron backscatter diffraction patterns as well as deformation state extraction. Validation on a realistically simulated undeformed single crystal nickel sample reveals mean accuracy of ~0.03 degrees and ~0.01% detector width across a large field of view. In combination with high angular resolution-EBSD, this method enables determination of strain states of reference patterns, hence, mapping of absolute strain maps becomes possible. Validation using noisy simulated deformed patterns with known deformation state and pattern center shows that the mean accuracy of shear strain and rotation components ~0.001 and normal strain ~0.002. Combined with an additional optimization step for the pattern center and orientation, an experimentally collected fatigue cycled TRIP steel data set has been able to validate the consistency of strain maps with the use of different reference patterns.