We use atomistic simulations to show that upon removal or insertion of atoms, misfit dislocations in Cu-Nb interfaces shift between two adjacent planes, forming pairs of extended jogs. Different jog combinations give rise to interface structures with unlike densities but nearly degenerate energies, making Cu-Nb interfaces virtually inexhaustible sinks for radiation-induced point defects and catalysts for efficient Frenkel pair recombination.

Interfaces act as obstacles to slip and sinks for radiation-induced defects. Hence, nanolayered composites that contain a large volume fraction of interfaces provide over an order of magnitude increase in strength and enhanced radiation damage tolerance compared to bulk materials. This paper shows the experimental and atomistic modeling results from a Cu-Nb nanolayered composite to highlight the roles of nanostructuring length scales and the response of interfaces to ion collision cascades in designing composite materials with high radiation damage tolerance. A. Misra, M.J. Demkowicz, and R.G. Hoagland are with Los Alamos National Laboratory, Los Alamos, NM, 87545; X. Zhang is now with the Department of Mechanical Engineering, Texas A&M University, College Station, TX. Dr. Misra can be reached at (505) 667-9860; e-mail amisra@lanl.gov.

Nanostructured materials contain an extremely high density of interfaces. The properties of these materials when exposed to extreme conditions of radiation dose, stress, deformation, or temperature are largely determined by defect-interface interactions. In this article, we review the present understanding of defect-interface interactions in single-phase and two-phase metal and oxide nanocomposites, emphasizing how interface structure affects interactions with point, line, and planar defects. We also review the crystallographic, chemical, and morphological stability of interfaces in different extreme environments: irradiation and mechanical deformation. Our current understanding of these topics prompts new questions that will maintain interfaces in crystalline solids at the frontier of materials research for years to come.

No abstract

The core of a nuclear reactor presents exceptionally stringent requirements for structuralmaterialsduetoitshightemperatureandintenseradiationaswellasitsneed for unfailing mechanical integrity [1][2][3][4] . Thus, candidate materials for nuclear applications must possess excellent irradiation tolerance, high strength, and thermal stability.However,thesepropertiesaredifficulttorealizesimultaneouslyinonematerialbecause of apparently intrinsic tradeoffs between them. Here we report a novel interface engineering strategy that simultaneously achieves superior irradiation tolerance, high strength, and high thermal stability in bulk nanolayered (NL) Cu-Nb composites. By synthesizing bulk NL Cu-Nb composites containing interfaces with controlled sink efficiencies, we design a material in which nearly all irradiation-induced defects are

No abstract

No abstract

No abstract