Composite Materials for Nuclear Applications: Metal Based Composites
Sponsored by: TMS Structural Materials Division, TMS: Composite Materials Committee, TMS: Nuclear Materials Committee
Program Organizers: Anne Campbell, Oak Ridge National Laboratory; Dong Liu, University of Oxford; Rick Ubic, Boise State University; Lauren Garrison, Commonwealth Fusion Systems; Peng Xu, Idaho National Laboratory; Johann (Hans) Riesch, Max Planck Institute for Plasma Physics
Monday 2:00 PM
March 15, 2021
Room: RM 52
Location: TMS2021 Virtual
Session Chair: Rick Ubic, Boise State University
2:00 PM
A Novel Processing Route for ODS Steel by Liquid Metallurgy: Shiqi Zheng1; Xiaochun Li1; 1UCLA
Oxide dispersion-strengthened (ODS) steel has long been pursued as an ideal material for high temperature and nuclear applications, due to the high thermal stability and strong pinning effect of the oxide particles. However, ODS steel is inherently difficult to manufacture at scale. Due to the poor wettability between oxide particles and molten steel, the oxide particles readily sinter during conventional liquid metallurgy processing, losing their intended effect. In this work, we present a novel concept of using micro-alloying elements, such as Nb and Cr, to improve the wettability between oxide particles and molten steel and, in turn, enable the production of ODS by slow solidification (<5 K/S). This novel processing route for ODS steel can circumvent the need for costly processing methods, such as rapid cooling and powder metallurgy, and allow large scale production of ODS steel for demanding applications.
2:20 PM
Competition between Void Evolution and Amorphization In Radiation-tolerant Nanocrystalline Cu-10at%Ta Alloy: Priyam Patki1; Wei-Ying Chen2; Janelle Wharry1; 1Purdue University; 2Argonne National Laboratory
The objective of this study is to understand the role of cascade morphology on the ion irradiation evolution of nanostructured Cu-10at%Ta alloy. The alloy is immiscible and has nanocrystalline Cu grains with a bimodal distribution of Ta nanoparticles. In this study, TEM in situ irradiation is conducted on Cu-10at%Ta lamellae using Ne, Kr, and Xe ions at temperatures ranging 100-400℃ to doses up to 10 displacements per atom (dpa). Irradiation-induced voids are observed at higher temperatures. Void onset dose decreases with cascade size, but void number density increases for smaller cascades. Irradiation-induced core-shell amorphization of Ta particles occurs at lower temperatures and with larger cascades. Amorphization and void formation compete at moderate temperatures. The point defect balance equations can explain these results by ascribing voids to the vacancy flux, and amorphization to the interstitial flux. This work provides insight into irradiation disordering of nanoparticles in oxide dispersion strengthened (ODS) alloys.
2:40 PM
Enhanced Microstructural Stability of ARB-processed Cu/Nb Nanolayers Under Heavy Dose Ion Irradiation at Elevated Temperatures: Madhavan Radhakrishnan1; Thomas Nizolek2; Mukesh Bachhav3; Yongqiang Wang2; Nathan Mara4; Osman Anderoglu1; 1University of New Mexico; 2Los Alamos National Laboratory; 3Idaho National Laboratory; 4University of Minnesota
Next generation nuclear reactors demand novel structural alloys capable to withstand high irradiation doses and harsh service conditions. In this work, bulk Cu/Nb nanolayered composites, produced by accumulative roll bonding process, were used as a model material to understand the synergistic effects of heavy irradiation doses and elevated temperatures on the stability of immiscible metallic interfaces and layered microstructures. Cu/Nb multilayers with an individual layer thickness of 25-500 nm were irradiated to a high dose of 200 dpa at 400°C and 600°C using Cu2+ ions with energies up to 7 MeV. Sub-surface microstructure examination revealed remarkable stability of Cu/Nb interface structures under irradiation and did not show any sign of morphological perturbation. Neither voids nor local chemical mixing across the interfaces were evident. The talk explores the correlation between the observed irradiation resistance and the defect sink efficiency of Cu/Nb interfaces using high-resolution electron microscopy and atom probe tomography.
3:00 PM
Evaluation and Irradiation of 14YWT Capacitive Discharge Resistance Welds: Calvin Lear1; Benjamin Eftink1; Hyosim Kim1; Todd Steckley1; Thomas Lienert2; Stuart Maloy1; 1Los Alamos National Laboratory; 2T.J. Lienert Consulting, LLC
Oxide dispersion strengthened (ODS) ferritic steels are promising candidates for use in extreme conditions, given their tolerance to radiation, resistance to creep, and maintained strength at high temperatures. However, the dispersoids responsible for these attributes are easily redistributed, agglomerated, and even altered in the prolonged high heat and localized melting of traditional fusion welding. A solid-state capacitive discharge resistance welding (CDRW) technique was used to cap thin walled, small diameter cladding tubes of the ODS alloy 14YWT. Microstructural evolution (e.g., recrystallization, oxide particle stability) in and around these joints was characterized using electron microscopy, while a mix of macro-mechanical testing and nano-indentation were used to probe the ductility and strength of the weld. Further, the most promising samples were irradiated using 5 MeV Fe2+ to a high dose (600 dpa, 450 °C) and characterized using electron microscopy to better understand their long-term stability.
3:20 PM
Irradiation Induced Forced Chemical Mixing and Local Hardening in Mechanically-processed Immiscible Zr/Nb Multilayers: Madhavan Radhakrishnan1; Thomas Nizolek2; Daniel Savage3; Marko Knezevic3; Nan Li2; Yongqiang Wang2; Mukesh Bachhav4; Boopathy Kombaiah4; Nathan Mara5; Osman Anderoglu1; 1University of New Mexico; 2Los Alamos National Laboratory; 3University of New Hampshire; 4Idaho National Laboratory; 5University of Minnesota
Past studies have shown that PVD-processed multilayers provide enhanced radiation damage mitigation due to interfaces-driven defects absorption. This work investigates the radiation resistance of bulk nanolayered zirconium-niobium composites subjected to high irradiation doses. Three Zr/Nb multilayers with individual layer thickness of 15-80nm were synthesized by accumulative-roll-bonding process. The multilayers were subjected to a dose of 82 dpa at 500°C using 7MeV Zr2+ ion beam. Cross-sectional TEM examination indicates that, in all multilayers, ion-irradiation has induced heterogeneous fragmentation of Zr, Nb layers and a chemically homogeneous mixed layer beneath the irradiated surface. The extent of sub-surface microstructural changes in multilayers agrees with the calculated damage profile. Light ion irradiation up to 1 dpa with He2+ ions was done to quantify the radiation defects-induced hardening in multilayers. The talk would focus on the correlation irradiation-induced local microstructural and compositional changes, and hardening response in layered structures using APT and micro-pillar compression tests.
3:40 PM
Mechanical Strength of Explosion Welded Thin Stainless-steel Cladding on Carbon Steel: Nathan Reid1; Lauren Garrison2; John Echols2; Kaustubh Bawane3; Jean Paul Allain4; 1University of Illinois Urbana Champaign; 2Oak Ridge National Laboratory; 3Idaho National Laboratory; 4Pennsylvania State University
Stainless-steel cladding plates have become increasingly popular for in-vessel components in both nuclear fission pressure vessel components as well as for nuclear fusion structural components in the blanket module. It utilizes the advantages of limiting expensive alloying elements and high activation at end-of-life while providing a corrosion resistant layer. In joining two dissimilar metals, the interface must be sufficiently bonded to avoid failure via interfacial delamination. The interfacial bond strength is the limiting factor in strength of these components under the stresses induced by load bearing and thermal gradients. Mechanical testing is performed to characterize the explosion welding of AISI 347 stainless cladding to a grade 70 carbon steel base. Compression shear testing is used to define the parameters for a tensile lap-shear testing for miniaturized neutron-irradiated tensile specimens. The composite strength is tested by impact and flexural testing. Fracture surface analysis is conducted to identify the modes of failure.
4:00 PM
Radiation Tolerance and Microstructural Changes of Nanocrystalline Cu-Ta Alloy to High Dose Self-ion Irradiation: Soundarya Srinivasan1; Chaitanya Kale1; Billy Hornbuckle2; Kris Darling2; Matthew Chancey3; Efrain Hernández-Rivera2; Yimeng Chen4; Thomas Koenig5; Yongqiang Wang3; Gregory Thompson5; Kiran Solanki1; 1Arizona State University; 2Army Research Laboratory; 3Los Alamos National Laboratory; 4CAMECA Instruments Inc; 5The University of Alabama
Radiation response of nanocrystalline Cu-Ta alloy is studied by irradiating with 4 MeV copper ions to doses of 1 dpa at 298 K; 10 dpa at 298, 573 and 723 K; 100 and 200 dpa at 298 and 573 K. Nanoindentation results for samples irradiated till 100 dpa at 298 and 573 K show exceptionally low hardening compared to candidate materials from literature. Microstructural characterization using TEM and APT, shows a stable nanocrystalline microstructure with minimal grain growth and a meagre swelling in samples irradiated to 100 dpa (~0.2%) and 200 dpa at RT, while no voids in those at 573 K. This radiation tolerance is partly attributed to the stability of Ta nanoclusters due to phase separating nature of the alloy. Additionally, the larger tantalum particles are observed to ballistically dissolve at >100 dpa and eventually precipitate as nanoclusters, replenishing the sink strength, which enhanced the material’s radiation tolerance.
4:20 PM
Synthesis and Irradiation Response of Hetero FeCr - Fe2O3 Interfaces: Benjamin Derby1; Jon Kevin Baldwin1; Djamel Kaoumi2; Danny Edwards3; Daniel Schreiber3; Timothy Lach4; Blas Uberuaga1; Nan Li1; 1Los Alamos National Laboratory; 2North Carolina State University; 3Pacific Northwest National Laboratory; 4Oak Ridge National Laboratory
Interfaces introduced in a structure act to influence the diffusion of solute atoms within that structure. In this work, a novel heterointerface between Fe8Cr and Fe2O3 is synthesized such that a network of misfit dislocations develops across the semi-coherent interface. This interface is synthesized by PVD sputtering a layered structure of a single-crystal, body-centered cubic Fe8Cr layer and a polycrystalline, rhombohedral Fe2O3 layer. This Fe8Cr-Fe2O3 thin film is then subjected to heavy Fe ion irradiation at 5.0 MeV and 250 oC. High-resolution electron microscopy is used to characterize the misfit dislocation network across the semi-coherent interface formed by the two materials with a misfit strain of 1.2 percent and to understand the material response under irradiation environments.
4:40 PM
Understanding Defect Recovery and Accommodation and Their Implications on Mechanical Performance in Irradiated Nanocomposite Materials: Michael Wurmshuber1; David Frazer2; Mehdi Balooch3; Inas Issa1; Andrea Bachmaier4; Peter Hosemann3; Daniel Kiener1; 1Montanuniversitaet Leoben; 2Los Alamos National Laboratory; 3University of California, Berkeley; 4Erich Schmid Institute of Materials Science
Nanostructured materials are a promising candidate for future application in highly irradiative environments, as the high density of interfaces within the material can act as sinks for radiation-induced lattice defects. This work focuses on the identification of the exact mechanisms of defect recovery, accommodation and evolution in irradiated composite materials. Nanostructured Cu-Fe-Ag alloys in three different conditions (ultra-fine grained, nanocrystalline and nanoporous) are fabricated and their response to irradiation with protons and helium ions is captured using advanced microscopy and nanoindentation testing. Qualitative models are established, linking the type and density of interfaces to the predominant defect mechanisms for both classical radiation damage and helium bubble formation and growth. By using these models to understand the response in defect structure and, consequently, mechanical properties upon irradiation of nanostructured materials, one more step towards the development and deployment of novel radiation-tolerant materials has been taken.