Advanced Real Time Imaging: Mechanical
Sponsored by: TMS Functional Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Alloy Phases Committee
Program Organizers: Jinichiro Nakano, MatterGreen; David Alman, National Energy Technology Laboratory; Il Sohn, Yonsei University; Hiroyuki Shibata, Tohoku University; Antoine Allanore, Massachusetts Institute of Technology; Candan Tamerler, University of Kansas; Noritaka Saito, Kyushu University; Neslihan Dogan, TU Delft; Zuotai Zhang, Southern University of Science and Technology; Bryan Webler, Carnegie Mellon University; Anna Nakano, US Department of Energy National Energy Technology Laboratory

Wednesday 8:30 AM
February 26, 2020
Room: Theater A-4
Location: San Diego Convention Ctr

Session Chair: Zuotai Zhang, Southern University of Science and Technology


8:30 AM  Cancelled
In-situ Observation of Plastic Deformation for Crystalline Materials: Masaki Tanaka1; 1Kyushu University
    We employed real time observation to understand the mechanism behind the plastic deformation of crystalline materials. In this presentation, firstly, the change in the work-hardening with tensile directions in silicon single crystals will be presented. Tensile tests were performed with silicon single crystals at between 1173 K and 1373 K with some tensile directions such as <134>, <110> and <100>. Kink bands were generated during the tensile deformation in stage I of the specimen with the <134> tensile direction. Stage I was not observed in the specimens with both the <110> and the <100> tensile directions where multiple slips started just after yielding. In addition to those observations, inhomogeneous deformation during the dynamic strain aging in low-carbon steels will also presented.

8:50 AM  Invited
In-situ Imaging of Nanocomposite Deformation: The influence of 3-D Interfacial Structure and Morphology on Mechanical Response: Nathan Mara1; Youxing Chen2; Justin Cheng1; Kevin Schmalbach1; Zhao Wang1; Nan Li3; Jon Baldwin3; R. Lee Penn1; David Poerschke1; Andreas Stein1; William Gerberich1; Irene Beyerlein4; 1University of Minnesota, Twin Cities; 2University of North Carolina, Charlotte; 3Los Alamos National Laboratory; 4University of California, Santa Barbara
    Nanocomposites exhibit enhanced strength, radiation damage tolerance, and deformability when compared with their coarser-grained counterparts. Here, a combination of in-situ SEM straining and post-deformation TEM reveals the mechanical behavior of two different classes of nanocomposites: 1.) nanolayered Cu/Nb containing interfaces with 3D (perpendicular to interface plane) chemical gradients and 2.) Tungsten-based 3D ordered nano/mesoporous composites consisting of a porous W scaffolding with silicon carbide infill. In-situ micropillar compression shows that the strength of Cu/Nb nanocomposites containing 3D interfaces is greater than those containing 2D interfaces. In the case of 3D mesoporous W-SiC, in-situ SEM indentation and micropillar compression coupled with digital image correlation reveal the distribution of local strains in the W ligaments. We will present our recent results on deformation of 3-D interfaces and nanostructures, describing the observed behavior mechanistically through the use of multiscale simulations.

9:10 AM  
In-situ Synchrotron 3D X-ray Imaging of Damage Initiation in CMC's Due to Oxidation Corrosion at High Temperature: Hrishi Bale1; Aly Badran2; David Marshall2; Robert Ritchie3; 1Carl Zeiss Microscopy Inc.; 2University of Colorado Boulder; 3University of California Berkeley
    Ceramic-matrix-composites (CMC’s) are being developed for service conditions of high temperatures and loads, well beyond the realm of current structural materials. Using various strategies and coatings with integral 3-D architectural designs, woven-CMCs make development of such ultrahigh-temperature structures feasible. Fracture assessment and lifetime prediction presents a formidable challenge, as reliable mechanical data and damage characterization must be achieved in 3-D at high temperatures. Using synchrotron X-ray micro-tomography to perform such characterization under load, oxidative environment and temperatures approaching 2000°C, we report here the contrasting damage modes in a woven SiC-fiber/SiC-matrix composite at high temperature. We observe for the first time in 3D, the degradation of BN interface and formation of damage initiation sites along the fiber-matrix interface layers. This ability to image complex 3-D materials undergoing failure at extreme temperatures opens new possibilities for evaluating CMC’s in real-time including the study of creep, load cycling and oxidation on the performance.

9:30 AM  
Real Time Imaging of Deformation Mechanisms in Boron Nitride Nanotube-metal Matrix Composites at Multiple Length Scales: Pranjal Nautiyal1; Benjamin Boesl1; Arvind Agarwal1; 1Florida International University
    BNNT is a fibrous nanomaterial with excellent strength and stiffness, which can be exploited to augment the mechanical properties of low-density metals like Al, Mg and Ti. The composites display a hierarchical microstructure, composed of a metal-matrix with dispersed ceramic nanotubes and interfacial products formed due to chemical reactions between the metal and BNNT during high-temperature processing. In-situ mechanical investigations are performed in high-resolution scanning electron microscope at multiple length-scales: nanoindentation for understanding interfacial stress-transfer, micropillar compression and microbeam bending to examine altered plasticity and crack propagation pathways due to nanotubes, and tensile testing to correlate bulk stress-strain response with deformation mechanisms. Real-time imaging shows an interplay of deformation mechanisms, such as nanotube re-alignment, crack-bridging, crack-deflection, nanotube-sliding and pull-out. These mechanisms have the net effect of significantly enhanced elastic modulus (two-fold improvement) and strength (400% enhancement), attesting the suitability of BNNT as a promising nanofiller to engineer advanced nanocomposites.

9:50 AM  Cancelled
In Situ TEM Characterizations on Mechanical Properties and Deformation of Metals: Qian Yu1; Xiaoqing Fu1; Qingqing Ding1; 1Zhejiang University
     The broad field of in situ electron microscopy (EM) instrumentation development holds great promise for addressing the structure-property relationship of materials due to its abilities to reach inherently high spatial resolution, to apply precise external fields and to perform accurate measurements of the corresponding responses simultaneously.Here, by coupling in situ TEM with other characterization techniques such as HRTEM and EDX, Titanium, Magnesium and high entropy alloys are investigated because of their broad prospects in industry. We studied some interesting issues including the oxygen strengthening effect in Titanium, the strong size effect on deformation twinning, the Re effect in Ni-based super alloy and the deformation mechanism of high entropy alloys.

10:10 AM Break

10:30 AM  Invited
Non-destructive Multi-property Determination under Extreme Conditions with Transient Grating Spectroscopy: Cody Dennett1; 1Massachusetts Institute of Technology
    Understanding the evolution of material performance in situ under extreme conditions remains a great challenge. Emergent behavior in these conditions, such as the transition from incubation to steady state void swelling under high-dose radiation, is often difficult to capture with ex situ data sampling protocols. Recently, the ability to non-destructively recover multi-property information in situ during exposure to extreme conditions has been demonstrated using transient grating spectroscopy (TGS). This all-optical method returns elastic mechanical and thermal transport properties with second-scale time resolution. Here, recent work using this methodology to track the evolution of Ni-based solid-solution alloys under high temperature exposure to ion beam irradiation using the in situ ion irradiation TGS (I3TGS) beamline at Sandia National Laboratories are described. Initial investigations on direct, real time thermal transport interrogation of several classes of phonon-mediated thermal materials during enhanced defect production will also be discussed.

10:50 AM  
Using the Digital Image Correlation Technique in Non-traditional Ways: Carl Cady1; Cheng Liu1; 1Los Alamos National Laboratory
    The digital image correlation technique has become a valuable tool for measuring deformation and damage in materials characterization. Details of the use of DIC in non-traditional ways to measure deformation and damage will presented for various types of material and loading conditions including strain rate effects, localization events and very large scale deformation. Examples for using DIC techniques for measuring delamination strength, shear strain and fracture toughness and other applications will be detailed. Some of the specific non-traditional techniques include large strain measurements (near 90% strain), subsurface delamination, crack boundary determination. It is hoped that this presentation can inspire novel approaches in the use of DIC as well as eliciting conversation on or for other non-traditional applications.