Tackling Structural Materials Challenges for Advanced Nuclear Reactors: Investigating Microstructural Features
Sponsored by: TMS Corrosion and Environmental Effects Committee, TMS Nuclear Materials Committee, TMS: Advanced Characterization, Testing, and Simulation Committee
Program Organizers: Miaomiao Jin, Pennsylvania State University; Xing Wang, Pennsylvania State University; Karim Ahmed, Texas A&M University; Jeremy Bischoff, Framatome; Adrien Couet, University of Wisconsin-Madison; Kevin Field, University of Michigan; Lingfeng He, North Carolina State University; Raul Rebak, GE Global Research
Tuesday 8:00 AM
October 11, 2022
Room: 330
Location: David L. Lawrence Convention Center
Session Chair: Lingfeng He, North Carolina State University; Raul Rebak, GE Global Research
8:00 AM
Microstructural Evolution of High-throughput Additively Manufactured 316L Stainless Steel with Increasing Hafnium Dopants: Laura Hawkins1; Jingfan Yang2; Miao Song3; Daniel Schwen4; Yongfeng Zhang5; Lin Shao1; Xiaoyuan Lou2; Lingfeng He4; 1Texas A&M; 2Auburn University; 3University of Michigan; 4Idaho National Laboratory; 5University of Wisconsin-Madison
Development of high throughput characterization methods is an important capability for reducing time and cost and increasing efficiency in qualifying a structural material for reactor use. Directed-energy-deposition (DED) was used to additively manufacture (AM) two compositionally graded 316L stainless steels to study the effects of Hf dopants on irradiation response: an as-built material and a thermo-mechanically treated recrystallized material to simulate a wrought grain structure. Microstructure and chemical composition of the AM materials were analyzed using transmission electron microscopy and associated spectroscopy techniques. Stacking faults in the unirradiated microstructure proved the rel-rod dark-field imaging technique is inefficient for quantifying dislocation loop size and density in AM materials. The Hf dopants can refine the grain structure to suppress nucleation of voids, irradiation-induced dislocation loops and grain boundary segregation. Compositionally gradient design using AM technique can be used for high throughput nuclear alloy development and qualification.
8:20 AM Invited
High-throughput Testing and Characterization of Materials For Nuclear Applications: Michael Short1; Myles Stapelberg1; Eleni Mowery1; Elena Botica Artalejo1; Gregory Wallace1; Tonio Buonassisi1; Isabel Alvarez1; 1Massachusetts Institute of Technology
Unlike progress in semiconductors, solar cells, or drug discovery, innovation in nuclear materials does not yet move at the speed of thought. We hypothesize that high-throughput workflow engineering centered around inference models between readily measurable properties and those of ultimate interest for nuclear structural materials (strength, ductility, toughness, thermal conductivity) can speed the pace of discovery, down-selection, development by a factor of 100. We employ a combination of thick-film physical vapor deposition or liquid-based combinatorial synthesis, followed by consolidation and microstructural optimization, and finally rapid measurements via in situ ion irradiation transient grating spectroscopy (I3TGS) and indentation plastometry during/between irradiations to correlate directly to fitness functions for each use case. We illustrate our ideas by tackling three systems: CuCr(Nb,Zr,Ti) alloys as RF antennas for plasma heating, plasma-facing first-wall high entropy alloys, and vanadium-based fusion structural materials, and will (hopefully) present our first results in this symposium.
8:50 AM
Phase-field Modeling of Radiation Induced Segregation for Multicomponent Alloys: Kinetic Monte Carlo and CALPHAD-Informed Simulations: Sourabh Bhagwan Kadambi1; Daniel Schwen1; Yongfeng Zhang2; Lingfeng He1; 1Idaho National Laboratory; 2University of Wisconsin Madison
Structural alloys under irradiation are known to undergo radiation-induced solute redistribution (RIS) at grain boundaries, leading to detrimental effects of intergranular corrosion and stress-assisted cracking. To better understand and mitigate such effects, improved models of RIS applicable to concentrated, multicomponent alloys, and mesoscale microstructures are needed. In this talk, we present a novel grand-potential-based phase-field model to account for the complete set of multicomponent kinetic and thermodynamic couplings between atoms and point defects in the Onsager transport equations. We demonstrate multiscale modeling capability by deriving the Onsager coefficient matrix from atomistic-based Kinetic Monte Carlo simulations. Model predictions and validations of RIS and the effect of defect production, grain boundary sink strength and density will be demonstrated for model FCC FeCrNi system. Finally, we will demonstrate the novel capability of the model to describe RIS in the presence of equilibrium segregation described using a density-based CALPHAD thermodynamics.
9:10 AM Invited
Microstructural Self-organization of Phase-separating Alloys during Irradiation into Global Compositional Patterns at Grain-Boundaries and Inside Grains: Pascal Bellon1; Gabriel Bouobda Moladje1; Sourav Das1; Soumyajit Jana1; Robert Averback1; 1University of Illinois at Urbana-Champaign
Nanoscale compositional patterns (CP) can be stabilized during irradiation in phase-separating alloy systems due to the competition between finite-range ballistic mixing and thermodynamically-driven decomposition. Here we extend past results on bulk patterning by studying CP at grain boundaries (GBs). We introduce a phase-field model to investigate the coupled evolution of concentration inside grains and at symmetric tilt grain boundaries, described as arrays of edge dislocations. In phase-separating binary alloys that undergo inverse Kirkendall effects due to vacancy-solute flux coupling, we show that irradiation-induced segregation competing with finite-range ballistic mixing can result in CP at grain boundaries. Furthermore, GB compositional patterning can co-exist with bulk patterning. These results are extended to segregation and precipitation on dislocation loops. These predictions are compared to past experimental results on precipitate evolutions in irradiated Ni-based alloys, and to new results in Al alloys. Consequences on hardness and microstructure stability under irradiation are discussed.
9:40 AM
Impact of Chemical Short-range Order on Radiation Damage in Fe-Ni-Cr Alloys: Hamdy Arkoub1; Miaomiao Jin1; 1Penn State University
Chemical short-range order (CSRO), a form of nanoscale special atom arrangement, has been found to significantly alter material properties such as dislocation motion and defect dynamics in various alloys. Here, we use Fe-Ni-Cr alloys to demonstrate how CSRO affects defect properties and radiation behavior, based on extensive molecular dynamics simulations. Statistically significant results are obtained regarding radiation-induced defect propensity, defect clustering, and elemental mixing as a function of dose for three CSRO levels. The perfect random solution as an energetically unfavorable state shows the strongest tendency to enable diffusion, while increasing CSRO degree causes decreasing diffusion, decreasing defect recombination, increasing number of residual defects, and decreasing ion-mixing. In addition, in the high-CSRO scenario, interstitial clusters are Cr-rich and interstitial loops preferentially reside in/near the Cr-rich CSRO domains. These new understandings suggest the importance of incorporating the effect of CSRO in investigating radiation-driven microstructural evolution.
10:00 AM Break
10:20 AM Invited
Hierarchical Microstructures: A Potential Route to Enhanced Stability in Structural Materials for Advanced Nuclear Reactors: Larry Aagesen1; Subhashish Meher1; Mark Carroll2; Laura Carroll3; Tresa Pollock4; 1Idaho National Laboratory; 2Federal-Mogul Powertrain; 3University of Michigan; 4University of California Santa Barbara
The drive to increase efficiency in nuclear energy systems is leading to the need for materials that operate at higher temperatures and stress levels for extended periods, while maintaining stable microstructures to ensure their performance is not compromised. A novel route to producing materials that can perform well in such environments is the creation of hierarchical microstructures. A hierarchical microstructure is a microstructure in which features are present at multiple length scales simultaneously. In this work, a hierarchical microstructure is fabricated in a nickel-base superalloy, featuring nanometer-size gamma precipitates inside larger gamma-prime particles, which are in turn embedded in the gamma matrix phase. The hierarchical features of the microstructure lead to enhanced stability of the gamma-prime precipitates during annealing; the particle size does not follow the expected t^(1/3) growth law predicted by the classic LSW theory. Phase-field simulations are used to understand the unexpected stability of the gamma-prime precipitates.
10:50 AM Invited
Synchrotron High-energy X-ray Studies of Nuclear Structural Materials: Xuan Zhang1; Meimei Li1; Jonathan Almer1; Jun-Sang Park1; Peter Kenesei1; Andrew Chuang1; Aniket Tekawade1; 1Argonne National Laboratory
Synchrotron x-ray diffraction- and imaging-based techniques are ideal tools for probing the evolution of deformation microstructures at multiple length scales and for revealing the underlying deformation mechanisms in bulk irradiated materials in situ and/or in 3D. Such tools are also advantageous in the study of additively manufactured materials. This talk will feature a few recent studies conducted at the Advanced Photon Source (APS) in Argonne National Laboratory, in particular, an in situ 3D characterizations of grain-level response to tensile deformation in neutron-irradiated Fe-9Cr ferritic alloy, and a study of porosity evolution under creep deformation in additively manufactured 316L stainless steel. The current development of the Activated Materials Laboratory, a new radiological facility to facilitate the study of nuclear materials at the APS that is built in conjunction with the APS-Upgrade project supported by the Nuclear Science User Facilities, will also be presented.
11:20 AM Invited
Radiation Resistance of MAX and MAB Phase Materials: Izabela Szlufarska1; Jianqi Xi1; Jun Young Kim1; Hongliang Zhang1; 1University of Wisconsin-Madison
MAX phase materials are 3D layered ceramics that have been shown an unprecedented tolerance to radiation-induced amorphization. However, unfortunately, MAX phases undergo radiation-induced crystalline-to-crystalline phase transformation, which compromises the many advantageous properties of these materials. In this talk, I will discuss how radiation resistance of Ti3SiC2 can be enhanced by engineering multi-layer systems with SiC and TiCx interfaces. I will show that unlike in metals, in ceramics interfaces are not necessarily beneficial to radiation resistance and that it is important to understand details of the defect energy landscape at and near ceramic interfaces. In addition, I will present our findings on radiation resistance of 3D layered borides (MAB phases) relative to MAX phases, I will discuss the role of a 2D Al layer in radiation resistance of the MAB phases, and finally I will introduce design rules we identified for design of MAB phases with enhanced radiation resistance.