Synergistic Irradiation, Corrosion, and Microstructural Evolution in Nuclear Materials: Irradiation Effects in Oxides
Sponsored by: TMS Structural Materials Division, TMS: Nuclear Materials Committee
Program Organizers: Djamel Kaoumi, North Carolina State University; Michael Short, Massachusetts Institute of Technology; Peter Hosemann, University of California, Berkeley; Stephen Raiman, University of Michigan; Raluca Scarlat, University of California, Berkeley; Aaron Kohnert, Los Alamos National Laboratory; Ryan Schoell, Sandia National Laboratory; Philip Edmondson, The University of Manchester; Celine Cabet, Commissariat a l'Energie Atomique

Wednesday 2:00 PM
March 2, 2022
Room: 202A
Location: Anaheim Convention Center

2:00 PM  
Investigation on the Impact of Proton-irradiation on Vibrational Properties of LiNbO3 with Raman Spectroscopy: Saqeeb Adnan1; Maha Yazbeck1; Yuzhou Wang2; Marat Khafizov1; 1The Ohio State University; 2Idaho National Laboratory
    Raman spectroscopy is utilized to determine the characteristics of displacement damage in Lithium Niobate (LiNbO3). Due to its linear and non-linear optical characteristics, piezoelectric, pyroelectric, and ferroelectric-paraelectric phase transition properties, LiNbO3 is widely used in opto-electronics and acoustic devices. Recently, it has grabbed attention as substrate material in semiconductor technology. Y/36°-cut LiNbO3 substrates were irradiated with protons. Analysis of Raman spectra of the proton-impacted region revealed the effect of irradiation damage on vibrational properties of LiNbO3 at two different wavelengths. A Peak shift, reduction of intensity and broadening of Raman E(TO) and A1(LO) mode peaks located at 369 and 878 cm-1, respectively, were observed. These are attributed to the lattice deformation and change in Nb-O bond stretching vibration caused by point defects. For nuclear energy applications, LiNbO3 is an attractive candidate for surface acoustic wave(SAW) devices. These devices offer a compact and wireless sensing solutions for temperature, pressure, and vibration.

2:20 PM  Cancelled
In Situ Observations of the Amorphization Behavior of Fe2O3, Cr2O3, and Al2O3 under Ion Irradiation: Angelica Lopez Morales1; Ryan Schoell1; Tiffany Kaspar2; Ben Derby3; Nan Li3; Dan Schreiber2; Djamel Kaoumi1; 1North Carolina State University; 2Pacific Northwest National Laboratory; 3Los Alamos National Laboratory
    Multilayers of Fe2O3 (hematite) and Cr2O3 of different thicknesses were grown using Pulsed-Laser-Deposition on an Al2O3 substrate. Focused Ion Beam (FIB) techniques were used to prepare Transmission Electron Microscopy (TEM) samples consisting of different thicknesses between 100 nm and 200 nm. The samples were cooled to 50 K in the TEM and irradiated in-situ with 1 MeV Kr ions. Bright Field imaging and diffraction patterns were used to determine the amorphization behavior of the three oxides at different doses. Partial amorphization of the oxides was observed depend on the oxide and its thickness. Besides, temperature-assisted partial recrystallization of the oxide layers was reported during post experimental “warm-up” to room temperature. Results are discussed with current models of amorphization including parameters such as crystal structure, atomic bonding, and energetics of defect formation and migration. The role that the interfaces and free surfaces play in this TEM experiments is also discussed.

2:40 PM  
Heavy-ion Irradiation Induced Cation Intermixing in Lanthanide Pyrochlores: Benjamin Derby1; Yogesh Sharma1; Matthew Chancey1; James Valdez1; Matthew Schneider1; Yongqiang Wang1; Aiping Chen1; Blas Uberuaga1; Nan Li1; Cortney Kreller1; Matthew Janish1; 1Los Alamos National Laboratory
    The unique structural arrangement of cations in lanthanide pyrochlores make them interesting candidates for actinide waste disposal and ion conduction-based devices. Understanding the physical mechanisms of cation transport in these systems is important to tuning their physical properties for functional use. In this work, we interface two pyrochlores, Gd2Ti2O7, which amorphizes easily, and Gd2Zr2O7, which is radiation-tolerant, by growing a bilayer structure. Irradiating this interface using Cu4+ heavy ions at 12 MeV energy to 0.2 - 0.8 dpa induced cation intermixing across the interface. The degree of cation intermixing at the interface was measured using analytical electron microscopy, namely energy-dispersive X-ray spectroscopy. By also analyzing superlattice reflection intensities as measured by four-dimensional scanning transmission electron microscopy across the interface, the cation disorder in each pyrochlore layer was determined. This technique may offer the potential to link strain in the material to cation disorder in these pyrochlore materials.

3:00 PM  
Study of Irradiation Defects Annealing in Thermally Grown Oxides by In Situ Raman Spectroscopy: Benoit Queylat1; Taeho Kim1; Adrien Couet1; 1University of Wisconsin, Madison
    In Pressurized Water Reactor, oxidation kinetics of zirconium alloys claddings is affected by irradiation of the oxide layer. In this environment, two phenomena dictate the oxide defect concentration evolution: creation by neutron irradiation and high-temperature annealing. While the impact of oxide irradiation on oxidation kinetics has been somewhat studied, there is very few data on defect annealing rate in PWR conditions. In this study, in situ Raman spectroscopy has been used to monitor irradiation defects annealing kinetics during corrosion. Two pre-oxidized zirconium alloys samples have been proton irradiated at temperature to simulate neutron irradiation effects in the oxide layer. The evolution of characteristic irradiation defects Raman bands has been monitored in-situ during subsequent corrosion tests in autoclave in high-temperature water, which allowed us to evaluate the annealing kinetics of irradiation induced defects in zirconia and its relation to oxidation kinetics. Other oxides relevant to nuclear materials are also examined.