Bulk nanolayered composites demonstrate superior radiation damage tolerance

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Journal of Materials Research cover featured a CMIME study showing significant voids at grain boundaries and grain growth after helium ion irradiation.

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Metallic materials able to survive extreme irradiation doses are needed for advanced nuclear energy and related applications. Researchers from the Laboratory’s Center for Materials and Irradiation and Mechanical Extremes (CMIME), in collaboration with Carnegie Mellon University and the Massachusetts Institute of Technology (MIT), engineered a novel material free of nearly all irradiation-induced defects. The team achieved this by synthesizing bulk nanolayered copper-niobium composites containing interfaces with controlled sink efficiencies. Advanced Materials published the research, and the Journal of Materials Research featured related work on its cover and as an invited feature paper.

The team investigated the irradiation damage behaviors of single crystal, coarse-grained, and nanograined copper films under helium ion implantation at 450 °C with different ion fluences. The researchers determined that copper-niobium nanolayered composites processed by accumulative roll bonding in sizes sufficient for structural applications exhibit a significantly lower density of radiation- induced voids than nanocrystalline copper of comparable grain size. Their results suggest that interphase boundaries in lamellar geometry may provide the optimal combination of point defect sink strength and low interface energy to achieve unprecedented stability in harsh radiation environments. Other bulk forms of nanomaterials, such as nanocrystalline metals, show grain growth and voids at boundaries during high-temperature irradiation and loss of damage tolerance.

References:

“Design of Radiation Tolerant Materials Via Interface Engineering,” Advanced Materials 25, 48 (2013); doi: 10.1002/adma.201303400. Authors include Weizhong Han (formerly with the Center for Integrated Nanotechnologies, MPA-CINT, now at Xian Jiaotong University, China), Nathan Mara and Amit Misra (MPA-CINT), Engang Fu and Yongqiang Wang (Materials Science in Radiation and Dynamics Extremes, MST-8), John S. Carpenter (Metallurgy, MST-6), Irene Beyerlein (Fluid Dynamics and Solid Mechanics, T-3), Michael Demkowicz (MIT), Subhasis Sinha and Anthony Rollett (Carnegie Mellon University).

“Irradiation Damage of Single Crystal, Coarse-grained, and Nanograined Copper under Helium Bombardment at 450 °C,” Journal of Materials Research, 28, 20 (2013); doi: 10.1557/jmr.2013.283. Authors are Weizong Han, E. G. Fu, Yongqing Wang, and Amit Misra (MPA- CINT), and Michael Demkowicz (MIT).

CMIME, an Energy Frontier Research Center funded by the DOE, Office of Science, Office of Basic Energy Sciences, sponsored the studies. CMIME aims to understand, at the atomic scale, the behavior of materials subject to extreme radiation doses and mechanical stress in order to synthesize new materials that can tolerate such conditions. Los Alamos leads the CMIME collaboration, which includes MIT, the University of Illinois at Urbana – Champaign, and Carnegie Mellon University. The work supports the Lab’s Energy Security mission area and the Materials for the Future science pillar. Technical contacts: Amit Misra and Irene Beyerlein