Advanced Characterization of Materials for Nuclear, Radiation, and Extreme Environments: Novel Techniques
Sponsored by: TMS Nuclear Materials Committee
Program Organizers: Samuel Briggs, Oregon State University; Christopher Barr, Department Of Energy; Emily Aradi, University of Huddersfield; Michael Short, Massachusetts Institute of Technology; Janelle Wharry, Purdue University; Cheng Sun, Clemson University; Dong Liu, University of Oxford; Khalid Hattar, University of Tennessee Knoxville
Monday 2:00 PM
November 2, 2020
Room: Virtual Meeting Room 13
Location: MS&T Virtual
Session Chair: Samuel Briggs, Oregon State University; Emily Aradi, University of Huddersfield
2:00 PM Invited
Characterization of Microstructure Evolution in Ceramic Materials Using Acoustic and Thermal Transport Measurements: Marat Khafizov1; 1Ohio State University
Progress in irradiation behavior of ceramics depends on availability of in-situ microstructure characterization tools. Development of methods relying on the sensitivity of material’s transport properties to crystalline defects will be reviewed. Optical spectroscopy is powerful for characterization of ceramics, but in-situ implementations have been limited to studies involving thermal annealing and charged particles. Alternatively in metals, in-situ electrical conductivity measurements under neutron environment have paved the way for fundamental understanding of irradiation behavior in metals. First, utility of thermal transport measurements utilizing modulated thermoreflectance method to isolating the impact of point defects, dislocation loops, and grain boundaries will be presented. Second, propagation of acoustic waves in solid materials monitored using picosecond ultrasonics as an attractive tool for characterizing grain microstructure in optically transparent ceramics will be discussed. Finally, interdigitated transducer surface acoustic wave approach to monitor early stages of radiation damage evolution under neutron irradiation will be introduced.
2:40 PM
Study on Hydrogen Isotopes Solubility and Diffusivity in Y- and Co-doped Barium-zirconates Using Tritium Imaging Plate Technique: M. Khalid Hossain1; Y. Hatano2; K. Hashizume1; 1Kyushu University; 2University of Toyama
Proton conducting oxides have a potential application in the tritium purification and recovery system of nuclear fusion reactors. Hydrogen distribution in such oxide materials is very fundamental and important, but its precise measurement is not so easy. In the present study, hydrogen solubility and diffusivity behavior in Y and Co doped barium-zirconates were studied using partially-tritiated deuterium vapor DTO (T 0.1%, ~2kPa) under two exposure conditions (673K, 2h or 873K, 1h) by tritium imaging plate (IP) technique. More than 98% dense specimens were prepared with conventional powder metallurgy using BaZr0.9Y0.1O2.95 (BZY) and BaZr0.955Y0.03Co0.015O2.97 (BZYC) powder. Cross-sectional T concentration profile of cut specimens showed that more T was diffused into BZY near-surface compared to BZYC. BZY shows both higher solubility and diffusivity than the BZYC, suggests that only a small amount of Y doping (10%) may play a vital role of enhancement of electrochemical activity in DTO exposed proton conducting BaZrO3.
3:00 PM
Mobility of Hydrogen in YH2 Probed by Nuclear Magnetic Resonance: Scarlett Widgeon Paisner1; Aditya Shivprasad1; Erik Luther1; 1Los Alamos National Laboratory
Metal hydrides are of interest for moderator materials in microreactors to improve efficiency of the fission reaction by thermalizing neutrons, allowing for minimization of the quantity of fuel required. Yttrium hydride (YH2-x) is an attractive option due to the high hydrogen content and the retention of the hydrogen beyond the operating temperature of 800 oC. However, the mobility of hydrogen at elevated temperature will impact the performance of these materials during operation. This study utilizes solid-state nuclear magnetic resonance spectroscopy (NMR) to determine the mobility of hydrogen in YH2-x powders as a function of temperature. YH2-x samples with different hydrogen contents were tested to investigate the role that stoichiometry has on the mobility. Preliminary data shows that a small fraction of hydrogen in YH1.80 is mobile at room temperature, and the fraction increases with temperature. The results will be discussed further in regards to hydrogen redistribution during reactor operation.
3:20 PM Invited
Nonlinear Ultrasound for Nondestructive Evaluation of Microstructural Defects: Katie Matlack1; 1University of Illinois Urbana-Champaign
Material damage in structural components is driven by nano- and micro-scale defects that evolve early in the component’s life. In metals, the interaction of an ultrasonic wave with these nano- and micro-structural defects, such as dislocations, precipitates, and micro-cracks, generates a second harmonic wave that is proportional to the acoustic nonlinearity parameter, which is an absolute and measurable material parameter. These defects are known to cause measurable changes in the acoustic nonlinearity parameter, which changes as the nano- and micro-structural defects evolve in the material. This talk will discuss how these nonlinear ultrasound (NLU) techniques can be used as a nondestructive evaluation tool to monitor nano- and micro-scale defects in metals, and thus characterize early-stage damage. I will focus on our recent work using NLU to monitor: (1) neutron radiation-induced embrittlement in nuclear reactor steels, (2) precursors to fatigue damage in structural metals, and (3) microstructure of additively manufactured metals.
4:00 PM Invited
In Situ Observation of Short- and Long-Timescale Material Property Evolution Under Extreme Conditions: Cody Dennett1; 1Idaho National Laboratory
Directly observing the evolution of material performance in-situ under extreme conditions remains a great challenge. Emergent behavior, such as the transition from incubation to steady state void swelling, is often difficult to capture in these conditions. To fill this gap, transient grating spectroscopy (TGS) has been used to collect multi-property information in-situ under high temperature exposure to ion beam irradiation. This all-optical method returns elastic 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 using the in situ ion irradiation TGS (I3TGS) beamline will be described. Tracking material property evolution during long exposure times (hours) provides a clear indication of when void swelling has occurred. On short timescales (seconds to minutes), observing rapid changes in thermoelastic properties as defect generation is initiated allows a unique window into bulk transient defect populations which are otherwise difficult to observe.
4:40 PM
STEM Characterization of Dislocation Loops for an Irradiated Model FCC Alloy: Pengyuan Xiu1; Lumin Wang1; Kevin Field1; 1University Of Michigan
In this study, we systematically developed the on-zone scanning transmission electron microscopy (STEM) methodology for imaging perfect and faulted dislocation loops in irradiated FCC materials, demonstrated on a model NiFe-20Cr alloy. Three major zone axes [100], [110], [111] were studied using on-zone STEM imaging. Simulated dislocation loop morphology maps were developed to aid in loop type identification. Other imaging techniques using S/TEM were conducted to compare with STEM bright-field and annular-dark-field imaging, including on-zone, two-beam conditions bright-field and Rel-Rod dark-field imaging in conventional TEM (CTEM). On-zone [100] STEM-BF imaging was identified as the preferred method to robustly detect and identify both types of loops in irradiated FCC alloys. Factors affecting imaging resolution and signal-to-noise-ratio including camera length and collection angle were also investigated. The developed on-zone STEM methodology is shown to be a marked improvement for loop characterization over the common Rel-Rod imaging techniques used in the nuclear materials field.
5:00 PM
Selective Irradiation Behavior in Dual Phase 308L Filler of SA508-304L Dissimilar Metal Weldment after Proton Irradiation: Zhen Li1; Xun Zhan1; Weicheng Zhong1; Benjamin Sutton2; Ovidiu Toader3; Gary Was3; Brent Heuser1; 1University of Illinois at Urbana-Champaign; 2Electric Power Research Institute; 3University of Michigan
Selective irradiation behaviors in mixed phase 308L filler of 508-304 DWM after proton irradiation were investigated to a depth of 0 to 10 µm. Ni-Si-Mn enriched precipitates were observed under SEM and TEM in δ ferrite, which is possibly attributed to the much higher diffusivity of solute elements in δ ferrite. STEM-EDS, TEM dark field imaging and diffraction patterns confirmed that these Ni-Si-Mn enriched precipitates were Mn6Ni16Si7. Voids were observed in γ austenite. The higher thermal expansion coefficient and faster void swelling rate of γ austenite might be responsible for its susceptible to the formation of voids. Ni-Si enriched clusters were detected at the edges of voids. However, diffraction patterns from the γ austenite, where containing voids, did not reveal the evidence of second phase. Therefore, these Ni-Si enriched clusters might be precursors of Ni-Si precipitates. In addition, irradiated induced Cr depletion, Si and Ni enrichment at γ austenite grain boundaries were detected under STEM/EDS.