Advanced Characterization Techniques for Quantifying and Modeling Deformation: Session I
Sponsored by: TMS Extraction and Processing Division, TMS Structural Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Materials Characterization Committee
Program Organizers: Arul Kumar Mariyappan, Los Alamos National Laboratory; Irene Beyerlein, University of California, Santa Barbara; Wolfgang Pantleon, Technical University of Denmark; C. Tasan, Massachusetts Institute of Technology; Olivia Jackson, Sandia National Laboratories
Monday 8:30 AM
March 20, 2023
Room: Aqua 311A
Location: Hilton
Session Chair: Dierk Raabe, Max-Planck Institute; Gregory Rohrer, Carnegie Mellon University
8:30 AM Invited
Quantifying Microstructural Evolution in Polycrystals: Gregory Rohrer1; Robert Suter1; Zipeng Xu1; Aditi Bhattacharya1; 1Carnegie Mellon University
Using high-energy diffraction microscopy, we have measured the microstructures of Ni and Fe polycrystals at multiple times during annealing. Thousands of grains and grain boundaries were tracked and their velocities and curvatures were classified by their crystallographic characteristics. Among the findings, two are noteworthy and will be discussed in this talk. First, the velocities vary with all five crystallographic grain boundary parameters. Second, grain boundary velocity is independent of grain boundary mean curvature. Because curvature is thought to be an important component of the driving force, velocity and curvature are expected to be correlated positively. However, the evidence for such a correlation is poor. An alternate mechanism for reducing the total grain boundary energy, based on the anisotropy of the grain boundary energy, will be discussed.
9:00 AM
Multiscale Characterization of Deformation and Defect Structures during Continuous Bending under Tension: David Fullwood1; Nathan Miller1; Addison McClure1; Michael Miles1; Marko Knezevic2; Brad Kinsey2; 1Brigham Young University; 2University of New Hampshire
Continuous bending under tension (CBT) offers a deformation route that delivers remarkable elongation to failure (ETF) in various materials. The strain path experienced by different regions of the sheet being deformed, along with the resulting defect structures at the micro scale, clearly play important roles in the improved forming behavior. This study applies digital image correlation (DIC) across the sheet edge in order to better understand the local deformation behavior, and correlates this with high resolution EBSD characterization of geometrically necessary dislocation structures. Initial observations indicate that the reverse bending step leads to lower GND formation at the outside of the sheet, modifying the local hardening behavior. The insights will be captured in a strain-gradient finite element model that is currently under development.
9:20 AM
Three-dimensional Assessment of Strain Localization at the Sub-grain Level of a Ni-based Superalloy at Low and High Temperature Using Laser Scanning Confocal Microscopy: Damien Texier1; Malo Jullien1; Ali Rouwane1; Julien Genée1; Jean-Charles Stinville2; Marc Legros3; Jean-Charles Passieux1; 1CNRS - Institut Clément Ader; 2University of Illinois, Urbana-Champaign; 3CEMES - UPR CNRS 8011
High resolution-digital image correlation (HR-DIC) techniques are well established to measure strain localization at the sub-grain level in polycrystalline materials. HR-DIC was generally conducted under scanning electron microscopy (SEM) to gain in spatial resolution and micrograph repeatability. However, HR-DIC under SEM only informs on the in-plane kinematics field at the surface of the deformed specimens. This technique is particularly appropriate when the out-of-plane motion related to the three-dimensional (3D) strain localization can be evaluated from another source, i.e., slip events in combination with EBSD. Non-crystallographic strain localization, such as grain boundary sliding, requires the development of 3D measurement techniques. Laser scanning confocal microscopy (LSCM) using near-UV monochromatic source provides less resolved in-plane micrographs but topographic information with a high accuracy (< 15 nm in height). A 3D formulation of the HR-DIC problem was thus implemented to evaluate the full-field strain localization in 3D in a Ni-based superalloy at different temperatures.
9:40 AM
The Effect of Hydrogen on Strain Gradient Hardening of Ni: Lai Jiang1; Michael Demkowicz1; 1Texas A&M University
We carried out an experimental investigation on the effect of hydrogen (H) on strain gradient hardening of pure Ni. Our approach relies on high fidelity characterization of residual curvature in microbend experiments carried out on foils electrochemically charged with H. To that end, we developed a technique for computational analysis of high-resolution optical micrographs. Combining our results with tensile yield strength and hardening coefficients obtained from micro-tensile tests enables us to determine the effect of H on the characteristic plasticity length scale of pure Ni. The implications of our findings for understanding of H embrittlement will be discussed.
10:00 AM Break
10:20 AM Invited
Mesoscale Simulation of Material Properties and Processing under Consideration of Microstructure, Chemistry and Damage Using DAMASK: Dierk Raabe1; 1Max-Planck Institute
The lecture presents a multi-physics, multi-mechanism, chemo-mechanical crystal plasticity and damage modeling package together with several applications to engineering alloys. The solution of such complex continuum mechanical boundary value problems requires constitutive laws that are based on material physics (considering microstructure, texture, chemistry, recrystallization, and damage) and that connect deformation, constitution, stress and damage at each material point. This task has been implemented in the free software DAMASK on the basis of the crystal plasticity method using a variety of constitutive laws and homogenization approaches.
10:50 AM
Towards Data-driven In-Situ Materials Testing in SEM: Fang Zhou1; 1Carl Zeiss Microscopy
In-situ materials testing in SEM is widely used to link materials properties to the microstructures. Machine learning based approach is very promising for finding diverse sets of materials microstructures correlated to certain properties or materials behavior which can accelerate the materials modeling and materials design. However, the machine learning approach is very data hungry and a sophisticated data-driven in-situ materials testing workflow in SEM is hardly available so far. In this work, a well-integrated solution for demanding data-driven in-situ testing in SEM, combining high resolution surface sensitive SEM imaging and EDS/EBSD analytical methods with materials testing stages is introduced. Further advancements such as automated feature tracking, autofocus and multiple regions of interest (ROIs) enable true one-button-start workflows and data-driven experiments. Data-driven automated in-situ materials testing solutions are crucial for collecting reliable experimental datasets for materials modeling via machine learning and, thereafter, predicting materials behavior during the in-situ testing experiment.
11:10 AM
Structure-property Correlations in Molecular Crystals Determined via Nanoindentation and Molecular Mechanics Modeling: Sushmita Majumder1; Gerrit Vreeman1; Javier Garcia Barriocanal1; Greg Haugstad1; Changquan Calvin Sun1; Nathan Mara1; 1University of Minnesota-Twin Cities
Mechanical properties of molecular crystals profoundly influence pharmaceutical milling and tableting operations due to the dependence of these processes on crystal fragmentation and plastic deformation phenomena. Although mechanical properties of individual molecular crystals have been studied previously, the correlation between these properties and underlying crystal structure remains poorly explored. We quantify the elastic modulus, hardness, and anisotropy of succinic acid via nanoindentation on different crystal planes. The obtained mechanical responses are correlated with slip plane orientation and slip directions analyzed via slip trace analysis and molecular mechanics modeling software. Through this correlation, molecular-level properties such as attachment energies and intermolecular interaction energies can be linked to mechanical behavior of different crystal faces under an applied load. This attempt to establish a fundamental understanding of crystal mechanical properties as a function of crystal geometrical features will help design of crystals optimized for milling and tableting operations.
11:30 AM
Integration of X-Ray Microscopy and Finite Elements into a Digital Twin: Mustafa Elsherkisi1; Theo Huyghe1; Maadhav Kothari2; Fabian Duarte Martinez1; Simon Gray1; Gustavo Castelluccio1; 1Cranfield University; 2Carl Zeiss Microscopy Limited
X-Ray microscopy (XRM) has revolutionised materials characterisation with impressive details and resolution. However, materials responses depend on myriads of attributes that cannot be entirely characterised by a single device. Thus, computational modelling can complement experimental efforts by providing estimations of attributes (e.g., stress) concurrent with the material characterisation. This presentation will focus on the integration of XRM with finite element models (FEM) to enable mapping of real-life cracks that are translated to realistic model meshes. We will demonstrate that the approach has been instrumental to uni-vocally discover the damage mechanism involved in stress corrosion cracking. We will further present an autonomous integration approach between XRM and FEM that can be implemented concurrently with the material characterisation. The seamless XRM-FEM exchange has the potential to control experiments based on magnitudes that are not measured but modelled.