Advanced Real Time Imaging: Emerging Imaging Techniques
Sponsored by: TMS Structural Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Alloy Phases Committee, TMS: Biomaterials 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; Noritaka Saito, Kyushu University; Anna Nakano, US Department of Energy National Energy Technology Laboratory; Zuotai Zhang, Southern University of Science and Technology; Candan Tamerler, University of Kansas; Bryan Webler, Carnegie Mellon University; Wangzhong Mu, KTH Royal Institute of Technology; David Veysset, Stanford University; Pranjal Nautiyal, University of Pennsylvania
Monday 8:30 AM
February 28, 2022
Room: 206A
Location: Anaheim Convention Center
Session Chair: Cody Dennett, Commonwealth Fusion Systems
8:30 AM Cancelled
Observing Nanoscale Defect Populations in Nickel through Transient Elasticity: Cody Dennett1; 1Idaho National Laboratory
Directly observing the evolution of lattice defects on the smallest scales is extremely challenging in metals, particularly for bulk specimens. Positron annihilation spectroscopy (PAS) can be used to measure nanoscale mono-vacancy and cluster populations, but PAS is not sensitive to interstitial-type defects. Here, we experimentally observe the presence of nanoscale vacancy and interstitial populations in pure nickel generated through ion beam bombardment by tracking changes in the surface Rayleigh wave velocity at varying defect generation rates. To do so, we use the in situ ion irradiation transient grating spectroscopy (I3TGS) beamline at Sandia National Laboratories to measure elastic property changes in an all-optical, non-contact manner. Unlike PAS, changes in the effective moduli are sensitive to both interstitial and vacancy-type defects. Our experimental observations are compared with cluster dynamics simulations of defect evolution in these conditions coupled with molecular dynamics calculations of the effect of various defects on the elastic moduli.
8:50 AM
Molten State Physical Properties of Divalent and Trivalent Alkaline Earth, Transition Metal, and Rare Earth Oxides: Jonathan Paras1; Osamu Takeda1; Mindy Wu1; Antoine Allanore1; 1Massachusetts Institute of Technology
Molten oxide physicochemical properties are difficult to study because oxides melt at high temperature, necessitating the use of containerless methods. Molten oxide droplets of Al2O3, Sc2O3, MgO, Y2O3, and La2O3 were suspended in the hot-zone of a floating zone furnace, wherein their density, melting points, and surface tensions were studied in-situ using live video. The performance of the chosen methods was validated against the properties of molten Al2O3, which has been well studied. To the best knowledge of the authors, our study represents the first time measurements of the surface tension and density of MgO and Sc2O3 have been reported. A trend between the surface tension and enthalpy of vaporization of molten oxides has been proposed. Comparisons were drawn with similar relationships presented for molten metals and semiconductors.
9:10 AM
Pseudo-4D Characterization of Lamella Orientations in Locked Al-Al2Cu Eutectic Colonies: Paul Chao1; George Lindemann1; Ashwin Shahani1; 1University of Michigan
We employed a novel imaging approach that combines in-situ X-ray radiography and ex-situ X-ray tomography to reconstruct the solid-liquid interface position within a solidifying Al-Cu metallic melt of near eutectic composition in three dimensions. The real time perspective of Al-Al2Cu eutectic pattern formation emerging from the melt provides unprecedented experimental evidence of the influence of an anisotropic solid solid interphase boundary energy on the pattern dynamics in a locked eutectic growth under transient solidification conditions. The wealth of information enabled us to quantify how the underlying eutectic microstructure adapts to oscillations in solid-liquid interfacial velocity and interfacial curvature. Our quasi 4D tomography approach holds broad application to the characterization of rapidly evolving fine microstructures, as it can temporally resolve the solidification process on the order of seconds and spatially resolves individual features (here, lamellae) on the order of micrometers.
9:30 AM
Analysis of In-situ X-ray Tomography Datasets of Dendritic Solidification Using 2D and 3D Machine Learning Algorithms: Tiberiu Stan1; Nathan Pruyne2; Jim James2; Marcus Schwarting2; Jiwon Yeom3; Ben Blaiszik2; Ian Foster2; Peter Voorhees1; 1Northwestern University; 2Argonne National Laboratory; 3Korea Advanced Institute of Science and Technology
Many advanced in-situ characterization techniques output large multimodal datasets that must be quantitatively processed to extract materials information. Image segmentation (the act of grouping the pixels of an image into useful parts) is at times the most time-consuming and subjective step in the analysis workflow. We show that it is possible to segment in-situ x-ray computed tomography datasets of dendritic solidification using a variety of 2D and 3D machine learning algorithms. The segmentations are compared both qualitatively (through visual inspection) and quantitatively using three computed metrics: pixel classification accuracy, intersection over union, and boundary F1 scores. Machine learning architectures, training techniques, hyperparameter selection, and general guidelines for implementation will be discussed. These advances in processing of large in-situ datasets will accelerate the rate of materials development, design, and discovery.
9:50 AM Break
10:10 AM
Challenges for Quantitative High-temperature Confocal Scanning Laser Microscopy: Understanding the Temperature Profile: Steven Britt1; P. Chris Pistorius1; 1Carnegie Mellon University
Despite heavy use of the high-temperature confocal scanning laser microscope, little work has been done to understand the temperature conditions within the sample. Obtaining a precise measurement of liquid metal is difficult because, unlike larger melts, a thermocouple cannot be immersed. The normal method of predicting the molten metal temperature, creating a linear regression from the observed temperature offsets when melting pure Fe and pure Cu, has not been tested to see that the relation holds independent of the metal observed. Furthermore, previous studies have asserted that between the top and bottom a molten droplet there exists a 20 K temperature difference. These studies have only modelled portions of the system, rather than including the entire mirror furnace chamber. This study seeks to test the material independence of the temperature compensation and to expand modelling efforts to include radiative heating of metals by the mirror furnace.
10:30 AM
Investigation of Echo Source and Signal Deterioration in Ultrasound Measurement of Metal Melt: Bitong Wang1; Andrew Caldwell2; Antoine Allanore2; Douglas Kelley1; 1University of Rochester; 2Massachusetts Institute of Technology
Ultrasound is a powerful tool for measuring flow and detecting impurities in opaque liquids, such as metal melts. Previously, we successfully demonstrated real-time imaging and flow measurement in gallium melt with this technique. However, ultrasound measurement in metal melts is not completely reliable because its operation depends on phenomena that are poorly understood. In this study, we focus on investigating the source of bulk echoes in gallium melt and the corresponding mechanism of ultrasound signal deterioration. Through electron microscopy examinations and ultrasound measurements, we determine that oxide inclusions are the main source of bulk echoes in gallium. By conducting a series of ultrasound measurements under different conditions, we demonstrated that the ultrasound signal deterioration is caused by two distinct factors: the loss of echoing objects and the degradation of wetting at the transducer surface. The possible mechanism of wetting degradation — ultrasound-induced cavitation — is further investigated through simulation and experiments.