Materials in Nuclear Energy Systems (MiNES) 2021: Advanced and Novel Materials- Session II
Program Organizers: Todd Allen, University of Michigan; Clarissa Yablinsky, Los Alamos National Laboratory; Anne Campbell, Oak Ridge National Laboratory
Thursday 8:00 AM
November 11, 2021
Room: Urban
Location: Omni William Penn Hotel
Session Chair: Calvin Lear, Los Alamos National Laboratory
8:00 AM Invited
Advanced Manufacturing for Novel Material Design and Development: Isabella Van Rooyen1; 1Idaho National Laboratory
Developing critical design criteria for new advanced reactor systems, components, and materials requires an understanding of both fabrication and irradiation environments during normal operating and accident conditions. Next-generation researchers and designers are therefore challenged by demands both to improve performance and to remain competitive by shortening development and commercialization for new nuclear reactors and systems. This provides unique and exciting opportunities for all contributors to this field of study. This presentation will offer a strategic overview on the role of advanced manufacturing during the realization of novel materials using case studies that detail current research for novel gradient and composite cladding and coatings, as well as fuel material systems.
8:40 AM
Additive Manufacturing (AM) of Oxide Dispersion Strengthened (ODS) FeCrAl Using In Situ Oxidation: Ty Austin1; Steven Zinkle1; Niyanth Sridharan2; 1University of Tennessee, Knoxville; 2Lincoln Electric
Ultra-high-performance structural materials are needed to improve the safety of current fission reactor designs and meet the demands of the extreme environments proposed in advanced reactor designs. Oxide dispersion strengthened (ODS) FeCrAl alloys offer a possible solution by utilizing finely dispersed precipitates to improve high-temperature strength and irradiation tolerance. ODS FeCrAl suffers from production issues like batch-to-batch variability, long lead-times, and low throughput. This work produces ODS FeCrAl using directed-energy deposition (DED) additive manufacturing (AM) by applying an oxygen-rich atmosphere during production to reduce production costs and time. Two different oxygen addition methods were examined across many processing conditions. Sample characterization demonstrates the ability to significantly increase sample oxygen content, produce near 100% dense parts, and produce fine-scale precipitation. Detailed characterization using TEM, APT, and post-build heat treatments have been done to examine the effects of the varied and complex processing conditions under AM on the morphology of these precipitates.
9:00 AM
Ultra-fine Lattice Wicking Structures Additively Manufactured from Tungsten: Carly Romnes1; Joseph Bottini1; Omar Mireles2; James Stubbins1; 1University of Illinois at Urbana-Champaign; 2NASA Marshall Space Flight Center
Additive manufacturing (AM) is particularly promising for manufacturing complex geometries from tungsten and other refractory metals, which are difficult to form using traditional processes. In this study, tungsten lattices were additively manufactured using various laser energy densities. These lattice structures have promising applications in both fission and fusion systems for heat transfer in applications which require radiation resistance at high temperatures. The goal of the work is to investigate the ability to adjust lattice type and printing parameters to vary the resulting fluid flow and mechanical properties of these lattices. To that end, lattice feature sizes were characterized using scanning electron microscopy and flow tests were performed with water and N2 to characterize the pressure drop across these samples. This work will help inform the development of tungsten lattices for nuclear systems, where tungsten is already of major interest for fusion systems for plasma facing and high thermal load structures.
9:20 AM
Innovative Elaboration Method of ODS Ferritic Steels Reinforced by Y2Ti2O7 Pyrochlore Phase Oxide: Guillaume Josserand1; Laurent Chaffron1; Pierre-François Giroux1; Joel Ribis1; David Simeone1; Thierry Gloriant2; 1CEA; 2INSA Rennes
Oxide Dispersion Strengthened (ODS) ferritic steels are promising candidates as cladding material for 4th Generation Sodium-cooled Fast nuclear Reactors. Conventional reinforcement is achieved by introducing titanium and yttrium oxide Y2O3 during ball milling with matrix steel powder. The dissolution of the oxide leads to an uncontrolled nucleation of complex oxides during the consolidation by hot extrusion. While some Y-Ti-O nano-particles are highly beneficial to the mechanical behaviour of the material, coarser ones – e.g. TiC, TiO2, Y2O3 – make it brittle. An innovative alloy-design approach is developed at CEA. Nanostructured Y2Ti2O7 pyrochlore phase oxides are elaborated by mechanochemical synthesis, and then introduced in ferritic matrix through ball milling. This way prevents from the appearance of deleterious coarse particles. Mechanical tests reveal a significant improvement in ductility and a low anisotropy, while maintaining a sufficient tensile strength up to 650°C. An extended cold-formability is expected from this innovative ferritic ODS grade.
9:40 AM
Strengthening Effects across Ultrasonic Additive Manufacturing (UAM) Interfaces: Michael Pagan1; Steven Zinkle1; Suresh Babu1; Takahito Ohmura2; 1University of Tennessee; 2National Institute for Materials Science
Ultrasonic additive manufacturing (UAM) technology provides the mechanism for creating advanced structural metals with embedded optical fiber sensors for in-situ strain monitoring in demanding environments such as nuclear reactors. The method for creating these complex structures involves bonding dissimilar metals using high strain rate deformation, although the mechanisms involved have yet to be explored before this study. The refined microstructure and strengthening mechanism across these embedded sensor interfaces are explored using nanoindentation and TEM techniques. Various plastic deformation mechanisms are explored at these interfaces. Refined grain structures, vacancy clusters, and elevated dislocation densities are found to be contributing factors to the observed strengthening across the interface, and a hardness superposition principle is used to describe the combination of these effects. A sensitivity analysis provides insight on their relative potential contributions. This study provides valuable insight into defect mechanisms across micron-scale embedded sensor interfaces which is vital to their technical implementation.
10:00 AM Break