Methods, Techniques, and Materials Discovery of Irradiation Effect Using In-situ Microscopy: In-situ Observation of Material Response under Extreme Environments
Sponsored by: TMS Structural Materials Division, TMS: Nuclear Materials Committee, TMS: Advanced Characterization, Testing, and Simulation Committee
Program Organizers: Wei-Ying Chen, Argonne National Laboratory; Xuan Zhang, Argonne National Laboratory; Kevin Field, University of Michigan; Donald Brown, Los Alamos National Laboratory; Aida Amroussia, GE Global Research
Monday 2:00 PM
March 20, 2023
Room: 25A
Location: SDCC
Session Chair: Donald Brown, LANL
2:00 PM Invited
Evolution of Vacancy/Interstitial Dislocation Loops in Pure Zr and Ti at Elevated Temperatures Observed by In-situ TEM Annealing: Fei Long1; Matthew Topping1; Zhongwen Yao1; Malcolm Griffiths1; Mark Daymond1; 1Queens University
Pure Zr and Ti were irradiated to two dpa levels by proton irradiation. The nature of the dislocation loops were determined by TEM STEM-HAADF imaging, and the amount of interstitial/vacancy loops were quantitatively analyzed. Both interstitial and vacancy <a> type loops were induced by the irradiation in the low dpa sample, while the <c> component loops were exclusively found to be vacancy type in the high dpa sample. In-situ TEM heating was applied to observe the evolution of dislocation loops during high temperature annealing at 500°C. The interstitial and vacancy <a> loops showed different growth behavior, through which the effect of point defect on the loop growth is evaluated. The <c> component loops showed higher resistance to heating. Through a combination of proton irradiation and in-situ TEM annealing in the pure system of Zr and Ti, the findings helped to explain growth behavior of neutron irradiated zirconium alloys.
2:30 PM Invited
Industrial Nuclear Materials Applications for In-situ Microscopy: Andrew Hoffman1; Rajnikant Umretiya1; Nathan Almirall1; Raul Rebak1; 1GE Research
Over the past few decades, advanced characterization techniques have significantly accelerated materials development. Often, correlative techniques combined with other experimental properties are key to bridging the gap between fundamental mechanisms and materials behavior in commercial nuclear reactor environments. In-situ irradiation combined with microscopy can play a key role as irradiation kinetics with time resolution are expensive due to the nature and cost of irradiations. In this talk we will discuss some key issues in the commercial reactor community, and propose how in-situ microscopy techniques could be leveraged to further our understanding of these materials and enhance commercialization of new materials for reactor environments.
3:00 PM
Transient Grating Spectroscopy of Defect Annealing Kinetics and Microstructural Evolution in Self-ion Implanted Tungsten with In-situ Annealing: Mohamed Abdallah Reza1; Kenichiro Mizohata2; Cody Dennett3; Guanze He1; Hongbing Yu4; Felix Hofmann1; 1University Of Oxford; 2University of Helsinki; 3Massachusetts Institute of Technology; 4Canadian Nuclear Laboratories
Using transient grating spectroscopy (TGS) with in-situ annealing, we study the evolution of crystal defects in self-ion implanted tungsten up to 800C for doses from 0.00032 to 3.2 dpa. A kinetic theory model interprets the underlying Frenkel pair concentrations from the measured TGS thermal diffusivities with high accuracy. Our results show a large removal of defects at ~350C, consistent with the temperatures for mono-vacancy mobility in tungsten. A near complete removal of defects was observed in the low dose samples (<0.0032 dpa) and ~70% for the larger doses. Ex-situ TEM confirmed the observation of remaining larger defects in the higher dose samples. These results present TGS as a tool for rapid quantification of irradiation-induced defects and their evolution in-situ, which is also sensitive to the smaller TEM invisible defects. The results also suggest that annealing at relatively modest temperatures may be used to significantly reduce irradiation-induced thermal diffusivity degradation.
3:20 PM Break
3:40 PM Invited
Simultaneous Proton Irradiation Changes Molten Fluoride Salt Corrosion Rates and Mechanisms: Weiyue Zhou1; Nouf AlMousa2; Yang Yang3; Kevin Woller1; Michael Short1; 1Massachusetts Institute of Technology; 2Princess Nourah Bint Abdulrahman University; 3Pennsylvania State University
Interest in deploying molten salt-cooled nuclear reactors continues to grow. Reactor designs are hindered partially by our lack of knowledge regarding the coupled effects of radiation and corrosion to be found within. To study this, we have constructed a simultaneous irradiation/corrosion facility, where material samples are exposed to concurrent proton irradiation and molten fluoride corrosion. Experiments on model and commercial alloys reveal radiation effects in structural materials as well as interactions between protons and the salt affect corrosion rates and underlying mechanisms. Some of these impacts can be highly transient, warranting both in situ irradiation and in situ observations. Tracking radiation counts via proton-gamma reactions during the experiments allows us to monitor the corrosion process in situ. Also, opportunities and challenges for future in-situ experiments will be discussed.
4:10 PM Invited
Is a TEM Foil “Bulk Enough” to Study the Parabolic Air-ingress Oxidation of W PFM in In-situ Environmental TEM?: Bharath Krupa Mekala1; Rajat Sainju1; Lichun Zhang1; Yuanyuan Zhu1; 1University of Connecticut
Pre-existing radiation-induced defects and surface reconstructions in the base tungsten armour could strongly influence the divertor’s response to the thermal oxidation in cases of air ingress accidents. However, oxidation data on irradiated tungsten are limited. While ion beam irradiation can serve as a good proxy for neutron damage, limited damage depth in tungsten poses a problem for the conventional Thermogravimetric Analysis (TGA) oxidation test. In this work, we combine the novel in-situ environmental TEM (ETEM) with ex-situ TGA and step-wise SEM/TEM characterizations, and develop a new oxidation kinetic test capability to facilitate the use of ion irradiated metals with limited damage depth to study radiation impact on oxidation.