Advanced Characterization of Materials for Nuclear, Radiation, and Extreme Environments: On-Demand Poster Presentations
Sponsored by: TMS Nuclear Materials Committee
Program Organizers: Cody Dennett, Commonwealth Fusion Systems; Samuel Briggs, Oregon State University; Christopher Barr, Department Of Energy; Michael Short, Massachusetts Institute of Technology; Janelle Wharry, Purdue University; Cheng Sun, Clemson University; Caitlin Kohnert, Los Alamos National Laboratory; Emily Aradi, University of Manchester; Khalid Hattar, University of Tennessee Knoxville
Friday 8:00 AM
October 22, 2021
Room: On-Demand Poster Hall
Location: MS&T On Demand
Session Chair: Emily Aradi, University of Manchester; Cody Dennett, Idaho National Laboratory
Poster
Effect of Dilute Magnetism in a Topological Insulator: Firoza Kabir1; 1University of Central Florida
Three-dimensional topological insulator (TI) has emerged as a unique state of quantum matter and generated enormous interests in condensed matter physics. Introduction of magnetism on the surface of a TI is essential to realize the quantum anomalous Hall effect and other novel magneto-electric phenomena. Here, by using a combination of first-principles calculations, magneto-transport, and angle-resolved photoemission spectroscopy (ARPES), we study the electronic properties of gadolinium (Gd)-doped Sb2Te3. Our study shows that Gd doped Sb2Te3 is a spin-orbit-induced bulk band-gap material, whose surface is characterized by a single topological surface state. We further demonstrate that introducing diluted 4f-electron magnetism into the Sb2Te3 topological insulator system by the Gd doping, creates surface magnetism in this system. Our results provide a new platform to investigate the interactions between dilute magnetism and topology in magnetic doped topological materials.
Poster
Modeling of Graphite Oxidation in Water Vapor Ingress Accidental Conditions for High Temperature Gas-cooled Reactors: Yi Je Cho1; Kathy Lu2; 1Virginia Tech; 2Virginia Polytechnic Institute and State University
Water vapor ingress is one of the probable accidents in high temperature gas-cooled reactors (HTGRs), which can oxidize vulnerable graphite components and fuel elements. Graphite oxidation involves burn-off that leads to deteriorating mechanical properties, formation of flammable hydrogen gas, and structural integrity loss. Two different types of graphite (nuclear and matrix graphite) are utilized in HTGRs, which show different oxidation phenomena. Also, the oxidation of the fuel elements occurs at two different scales and needs to be considered simultaneously in order to understand the oxidation behaviors during an accident. In this study, a modeling framework is established to investigate the oxidation behaviors of graphite in water vapor. The model consists of a prismatic fuel block with a coolant channel to predict the water vapor permeation and location effects. The results are compared with experimental results.
Poster
Prediction Thermo-physical Characteristics Nickel-based Superalloys Directional Crystallization: Alexander Glotka1; Vadim Olshanetskii1; 1Zaporizhzhia Polytechnic National University
The paper presents a comparative analysis of the practical and calculated values of the thermophysical properties of heat-resistant nickel alloys of directional solidification. Using an empirical approach, new ratios of the elements K and K have been obtained for the first time, which take into account the combined effect of alloying elements on the temperature of multicomponent compositions of cast heat-resistant alloys. The calculated values of the critical temperatures for the Ni-6Al-9Co-8W-4Re-4Ta-1.5Nb-1Mo-0.15C system are in good agreement with the experimental ones. The dependence of the K ratio on the alloying system; the influence of alloying on the liquidus temperature of the alloys is studied. The ratios of the content of alloying elements and regression models that can be used to predict the width of the crystallization temperature range and the optimal homogenization temperature for a particular alloy are presented.
Poster
Tensile Performance of Diffusion Bonded AA6061-AA6061 Cladding-Cladding Interface for Application in U-10Mo Monolithic Fuel Plates: Abhishek Mehta1; Jeongmin Woo1; Jeffrey Giglio2; Jan-Fong Jue2; Dennis Keiser2; James Cole2; Yongho Sohn1; 1University of Central Florida; 2Idaho National Laboratory
The AA6061 claddings produced by hot isostatic pressing is an important structural component of the high performance, monolithic U-10Mo fuel system for research and test reactors. In this study, mechanical integrity of diffusion bonded AA6061 alloys were examined. Solid-to-solid diffusion bonding was performed by annealing two AA6061 alloys at 560 °C for 1.5 h, and subsequently cooled via three different cooling methods: furnace cooling, air cooling, and water quenching. Dog-bone shaped tensile specimens, with ~ 10 mm in gauge length and 1.5 mm in thickness, were fabricated from the diffusion couples by electro-discharge machining. Yield strength (%EL at failure) of furnace cooled, air cooled and water quenched specimens determined was 82-89 (10-30%), 112-116 (10-14%), and 149-164 (10-17%) MPa, respectively. The variation in mechanical behavior was interpreted with respect to microstructural development associated with precipitation of Mg2Si at the diffusion bonded interface during cooling with the aid of time-temperature-transformation diagram.
The Effect of Rotary Swaging on Zirconium Alloys and its Microstructure Property Correlation: Gaurav Singh1; Raviraj Verma1; K I Vishnu Narayanan2; Umesh Kumar Arora2; R. Jayaganthan1; 1Indian Institute of Technology Madras; 2NFC Hyderabad
Zirconium alloy shows good combination of strength and ductility, low neutron absorption cross section and excellent corrosion and oxidation resistance. In this study, effect of true strain and feed rates (0.7 m/min, 1.25 m/min and 2 m/min) of rotary swaging process on microstructural behaviour of zircaloy have been performed. Effect of strain and feed rates on surface and centre of swaged and annealed samples were studied using transmission electron microscopy (TEM). Microhardness measurements were performed from edge to centre for swaged and annealed conditions. The swaged samples are exhibiting more deformed microstructure at specimen edge compared to centre location at higher true strain (=0.38), while uniform deformation has been observed in annealed samples. The microstructural inhomogeneities in swaged samples were tandem with microhardness results.