Advanced Characterization Techniques for Quantifying and Modeling Deformation: Session VIII
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 Underwood Jackson, Sandia National Laboratories
Thursday 2:00 PM
March 3, 2022
Room: 207A
Location: Anaheim Convention Center
Session Chair: Kyle Johnson, Sandia National Laboratories; Amy Clarke, Colorado School of Mines; Aritra Chakraborty, Los Alamos National Laboratory
2:00 PM Invited
Multiscale Characterization of Metallic Alloy Microstructures and Links to Properties: Amy Clarke1; Benjamin Ellyson1; Likith Sri Ranga Jai1; John Copley1; Kester Clarke1; Jonah Klemm-Toole1; Kamel Fezzaa2; Francisco Coury3; 1Colorado School of Mines; 2Argonne National Laboratory; 3Federal University of São Carlos
Today, state-of-the-art characterization techniques available in the laboratory and at national user facilities are enabling unprecedented, multiscale in-situ/ex-situ studies of structural alloys and new insights into processing-microstructure-property-performance relationships. In this work, transformation- and/or twinning-induced plasticity, TRIP or TWIP, respectively, are highlighted in structural metallic alloys that achieve desirable strength/ductility combinations, from quasi-static to dynamic deformation. For example, microstructures during/after deformation, including in-situ synchrotron x-ray imaging and diffraction during high strain rate testing up to 2 x 10^3 s^-1, along with complementary post-mortem characterization, reveal evidence of TRIP and TWIP in metastable titanium and multi-principal element alloys. These deformation mechanisms can be tailored to design the microstructures, properties and performance of structural metallic alloys for engineering applications.
2:30 PM
Estimation of Micro-Hall-Petch Coefficients in Mg-4Al as a Function of Grain Boundary Parameters: Mohsen Taheri Andani1; Aaditya Lakshmanan1; Yung Suk Jeremy Yoo1; Veera Sundararaghavan1; John Allison1; Amit Misra1; 1University of Michigan
Theoretical works have reported that the grain boundaries (GBs) parameters play a significant role in determining the Hall-Petch in metallic materials. However, experimental measurements to validate these studies are still limited. In this study, a high-resolution electron backscatter diffraction technique coupled with a dislocation pile-up model is utilized to quantify the barrier strength of specific GBs to basal/prismatic slip systems, referred to as the basal/prismatic micro Hall-Petch slope, in Mg-4Al. The micro Hall-Petch slopes are then correlated with GBs parameters, and the results indicate that the angle between the two slip plane traces on the GB plane and the angle between the slip directions are the most sensitive parameters affecting the micro Hall-Petch slope. This work will provide new insights into the understanding of the texture and grain size in the plasticity of Mg alloys.
2:50 PM
The Early Stage of Deformation-induced Dislocation Patterning Studied by DFXM: Albert Zelenika; Can Yildirim1; Carsten Detlefs1; Henning Poulsen2; Grethe Winther2; 1ESRF; 2DTU
The early stage of dislocation patterning in aluminium crystals (AA1090) oriented for conjugate double slip has been mapped out in 3D by Dark Field X-ray Microscopy (DFXM). Crystals of the same initial orientation were deformed up to 3.5% elongation ex-situ. The angular spread caused by the evolution of dislocation boundaries in bulk volumes of up to 225x750x170 µm3 was characterized. The size of the volume mapped makes patterns with a large length scale visible. In addition, the high angular resolution of DFXM enables detection of boundaries with small misorientation. For these reasons, clear patterning is revealed at an earlier stage than previously observed. The evolution of the patterns is presented and compared to the patterns formed at higher plastic strains.
3:10 PM Invited
Capturing Deformation Mechanisms in Additively Manufactured Parts through High-fidelity Modeling and In Situ Computed Tomography: Kyle Johnson1; Thomas Ivanoff1; Philip Noell1; Nathan Heckman1; John Emery1; 1Sandia National Laboratories
Improvements in characterization methods have occurred at a rapid pace in recent years. In situ, sub-micron resolution computed tomography (CT) systems at the lab-scale are one such improvement. In parallel, high performance computing power has vastly increased. We are now reaching a point in both computational capability and temporal and spatial characterization fidelity where limits of homogenization theory are being approached, and scale separation is no longer a necessary assumption for structural components. This intersection presents exciting opportunities for both experimentation and computational modeling. This talk will discuss ongoing work to fuse high resolution in situ CT with high-fidelity modeling in order to predict deformation and failure mechanisms in structural metals. As an example, a recent effort will be presented focusing on characterizing and modeling regional property effects on deformation and localization behavior in additively manufactured parts. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.
3:40 PM Break
3:55 PM
Coupling In-situ SEM Experiments with Acoustic Emission to Unravel the Underlying Deformation Mechanism in Metals: Mostafa Omar1; Jaafar El-Awady1; 1Johns Hopkins University
Metals exhibit different deformation mechanisms. Conventional load-displacement curves are inadequate for discrimination between active mechanisms that temporally overlap. Dislocations, twinning, and cracks generates different acoustic emission (AE) signatures when activated. In this work, AE technique is coupled with in-situ micromechanical testing inside the SEM to study the deformation of microcrystals. By simultaneously recording the generated AE signals while running microcompression tests, correlations were drawn between the AE wave characteristics and the generated stress-strain curves. AE analysis in both time and frequency domains can differentiate between various active sources and probe the underlying deformation kinetics. In addition, statistics associated with strain bursts in single crystal Ni microcrystal are discussed as well as the impact of using stiff vs. laterally compliant compression tips on the generated signals.
4:15 PM
Grain Environment Dependent Deformation Twinning in a TWIP Steel: A 3DXRD Study: James Ball1; Stefan Michalik1; Oxana Magdysyuk1; Thomas Connolley1; David Collins2; 1Diamond Light Source; 2University of Birmingham
Three-dimensional X-Ray diffraction (3DXRD) was employed to provide micromechanical insights from a coarse grain, high-Mn TWIP steel derivative during in-situ deformation. This work showcases a new capability to perform synchrotron-based Far Field 3DXRD experiments at the I12 Beamline, Diamond Light Source, as well as the suitability for quantifying grain specific crystallography, stress state, position and neighbouring crystal environmental detail. This was utilised to deduce the behaviour of individual austenite grains during loading; it was possible to depict grain specific conditions that triggered twinning events. This included new observations of sudden crystal rotations at the inception of a twin, thought to be a necessary condition for the grain to accommodate local displacive changes. Along with independent verification of the diffraction observations via offline electron microscopy methods, this work contributes to the fundamental understanding of ultra-high ductility steels with transformation induced mechanism behaviour.