Characterization of Nuclear Materials and Fuels with Advanced X-ray and Neutron Techniques: X-ray Diffraction/Scattering I
Sponsored by: TMS Structural Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Nuclear Materials Committee
Program Organizers: Xuan Zhang, Argonne National Laboratory; Jonathan Almer, Argonne National Laboratory; Maria Okuniewski, Purdue University; Joshua Kane, Idaho National Laboratory; Donald Brown, Los Alamos National Laboratory; J. Kennedy, Idaho National Laboratory; Arthur Motta, Pennsylvania State University

Monday 8:30 AM
March 15, 2021
Room: RM 51
Location: TMS2021 Virtual

Session Chair: Jonathan Almer, Argonne National Laboratory; Maria Okuniewski, Purdue University


8:30 AM  Invited
Synchrotron High-energy X-ray Studies of Nuclear Reactor Materials: Meimei Li1; Xuan Zhang1; Jonathan Almer1; Jun-Sang Park1; Peter Kenesei1; Andrew Chuang1; 1Argonne National Laboratory
    Recent advances of synchrotron X-ray techniques have provided us unprecedented time and spatial resolution and new in situ capability with complex sample environments, shedding new light into the mechanisms and pathways of microstructural evolution and its correlation with material’s macroscopic behavior. Synchrotron high-energy X-rays are ideal tools for probing defect formation, deformation dynamics, and phase transformation of bulk materials in real time in realistic conditions. Research of nuclear reactor materials conducted at the Advanced Photon Source will be highlighted, including in situ deformation studies of ferritic and austenitic steels with wide-angle X-ray scattering, small-angle X-ray scattering, and in situ 3D characterization by high-energy X-ray diffraction microscopy. In situ metal additive manufacturing studies with high-speed X-ray diffraction and imaging, and X-ray tomography of porosity distribution in additively printed materials and stress corrosion cracking will also be presented.

9:00 AM  
Evolution of Stresses in Deformation Twins in the Plastic Zone Using Three-dimensional Synchrotron X-ray Diffraction: Hamidreza Abdolvand1; Karim Louca1; Charles Mareau2; Marta Majkut3; Jonathan Wright3; 1Western University; 2Arts et Métiers ParisTech; 3European Synchrotron Radiation Facility (ESRF)
    Hexagonal closed-packed (HCP) metals have been extensively used in various industrial sectors. Understanding the deformation mechanisms of HCP metals at the grain-scale is a necessity for developing predictive models that can be used for the performance or failures analysis of engineering components. One of the common deformation mechanisms in HCP metals is deformation twinning. In this study, average grain stresses and size of the tensile twins are investigated with respect to their parent grains. In-situ three-dimensional X-ray diffraction (3D-XRD) is used for capturing grains center-of-masses (COMs), orientations, strains, and volumes. The evolution of stresses in twin and parent pairs are studied in detail, both at the early stages of plasticity and further into plastic zone.

9:20 AM  
Characterization of Long Range Ordering in Ni-based Alloys with Ex-situ and In-situ Synchrotron X-ray Diffraction: Nicholas Aerne1; David Sprouster2; Fei Teng3; Mehmet Topsakal4; Adrien Couet5; Kumar Sridharan5; Julie Tucker1; 1Oregon State University; 2Stony Brook University; 3Idaho National Lab; 4Brookhaven National Lab; 5University of Wisconsin-Madison
    The formation of long-range order in high-Cr, Ni-based alloys reduces the ductility of the microstructure. This loss of ductility is of concern to the service life of components (i.e. steam generator tubing) in pressurized water reactors. In this research, isothermal aging at temperatures between 330-475 C of model Ni-Cr, and commercial 690, 625, and 625P alloys has been performed up to 10,000 and 21,000 hours, respectively. Additionally, 10 alloys were proton irradiated to 1.5 dpa to enhance the Ni2Cr ordering. The alloys were characterized with ex-situ and in-situ synchrotron x-ray diffraction measurements. Ex-situ measurements were performed to reveal the microstructure evolution and quantification of the Ni2Cr ordering. In-situ experiments with temperatures up to 750 C were carried out to observe the critical transformation temperature. Preliminary results show lattice contraction at 15,000 hours aged at 475C in Alloy 690, indicative of Ni2Cr formation as seen in model alloys.

9:40 AM  
Irradiation-induced Effects in HT-UPS Steel Using Far-field X-ray Diffraction and Grain Tracking Analysis: Sri Tapaswi Nori1; Alejandro Figueroa1; Jonova Thomas1; Hemant Sharma2; Jun-Sang Park2; Peter Kenesei2; Jonathan Almer2; Maria Okuniewski1; 1Purdue University; 2Argonne National Laboratory
    High-temperature ultrafine-precipitate-strengthened (HT-UPS) steel is an austenitic stainless steel, known for its high-strength and creep resistance at elevated temperatures (>400℃). It is a candidate structural material for advanced nuclear reactors. However, its neutron irradiation tolerance is not well known. Hence, this research utilized far-field high-energy diffraction microscopy experiments which were conducted on neutron-irradiated (0.3 dpa at 600℃) HT-UPS steel sample to obtain diffraction patterns, both pre- and post-irradiation within the same region of the specimen. A unique grain tracking methodology was used by comparing the diffraction spots of pre- and post-irradiation states to reveal the evolution of grains with neutron irradiation. These results are being further validated using higher resolution three-dimensional electron back scattered diffraction/scanning electron microscopy that utilizes a serial sectioning approach. Thus the grain evolution and its validation, along with the correlation with lower length scale features such as precipitates, will be presented.

10:00 AM  Invited
Multimodal Synchrotron Characterization of Transmutation Products in Structural Materials: David Sprouster1; J Trelewicz1; D Morrall2; X Hu2; C Parish2; B Wirth3; Y Katoh2; L Snead1; 1Stony Brook University; 2ORNL; 3University of Tennessee, Knoxville
    Structural materials in advanced fission and fusion reactors are exposed to extreme radiation conditions, that over time lead to the accumulation of transmutation products. These transmutation products have deleterious effects on the thermomechanical properties including severe toughness degradation and thermal conductivity decrease. Recent neutron irradiation experiments with mixed energy spectra have in fact demonstrated that refractory metals and alloys, in particular tungsten, are appreciably susceptible to the formation of nanometer-scale features involving transmutation products (Re and Os), which ultimately degrade the mechanical properties and rapid embrittlement at low irradiation doses. In this work, we employ multimodal synchrotron-based characterization methods to gain insights into the size, shape, and structure of transmutation products for a series of neutron irradiated tungsten specimens. The microstructural insights from the synchrotron characterization compliment modelling and electron microscopy results and shed new light on the size distributions and crystallographic phases of transmutation products that ensue after irradiation.

10:30 AM  
4D X-ray Diffraction Microscopy Study of Tensile Deformation of Neutron-irradiated Fe-9Cr Alloy: Xuan Zhang1; Dominic Piedmont2; Jun-Sang Park1; Peter Kenesei1; Jonathan Almer1; Meimei Li1; 1Argonne National Laboratory; 2University of Illinois at Urbana-Champaign
    The tensile deformation of two neutron-irradiated (450C/0.1dpa and 300C/0.1dpa) Fe-9Cr samples were studied at the Advanced Photon Source by far-field high-energy x-ray diffraction microscopy (ff-HEDM) at intermittent loading steps to 4.5% strain, along with in-situ wide-angle x-ray scattering (WAXS) during loading. Their unirradiated counterpart was also studied in the same way. In addition, for all three samples, the undeformed and the deformed grains within the same volume were characterized by near-field HEDM (nf-HEDM). In this talk, I will provide some key results from this comprehensive 4D (3D + deformation state) dataset, focusing on the microstructural evolution at the meso scale (grain/sub-grain scale), including the grain morphology and orientation change, and the residual strain buildup. This comprehensive dataset provides unpreceded information regarding the effect of neutron irradiation to the deformation mode of the Fe-9Cr ferritic alloy, across multiple length scales from macro to meso to micro.

10:50 AM  
In-Situ XRD Study of Alloy 709's Mechanical Behavior for Advanced Fast Reactor Applications: Dominic Piedmont1; Donghee Park1; Victoria Riso1; Xiang Liu1; James Stubbins1; 1University of Illinois at Urbana Champaign
    In-situ XRD information on Alloy 709’s mechanical response at various temperature and strain rate regimes was collected. From the resulting tensile tests, an optimized constitutive equation was developed. The simultaneously collected Wide and Small Angle X-ray Scattering (WAXS/SAXS) data was used to support the material representation given in the models. WAXS data revealed dislocation behavior and the presence of a secondary phase which resulted in load partitioning. Whereas, SAXS data was used to observe the volume fraction of phases as well as voids and their associated evolution and growth. With support from XRD analysis, an understanding and justifications for the resulting deformation constants within constitutive equations can be established. A complete picture of Alloy 709’s microstructural response to various temperature and strain rate deformation regimes is constructed from three observables: phase-based peak broadening, phase-based lattice strain, and void volume evolution, which are captured in an optimized set of constitutive equations.