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Title:In situ transmission electron microscopy ion irradiations of model iron-chromium alloys
Author(s):Tomchik, Carolyn A.
Advisor(s):Stubbins, James F.
Department / Program:Nuclear, Plasma, & Rad Engr
Discipline:Nuclear Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Iron-chromium (FeCr)
ion irradiation
nuclear materials
Abstract:Iron-chromium alloys are used as a model to study the microstructural evolution of defects in irradiated structural steel components of a nuclear reactor. We examine the effects of temperature and chromium concentration on the defect evolution and segregation behavior in the early stages of damage. In situ irradiations are conducted in a transmission electron microscope (TEM) at 300°C and 450°C with 150keV iron ions in single crystal Fe14Cr and Fe19Cr bicrystal to doses of 2E15 ions/cm^2. The microstructures resulting from annealing and irradiation of the alloy are characterized by analysis of TEM micrographs and diffraction patterns and compared with those of irradiated pure iron. We found the irradiation temperature to have little effect on the microstructural development. We also found that the presence of chromium in the sample leads to defect populations with small average loop size and no extended or nested loop structures, in contrast to the populations of large extended loops seen in irradiated pure iron. A very weak dependence was found on the specific chromium content of the alloy. Chromium was shown to suppress defect growth by inhibiting defect mobility in the alloy. While defects in pure iron are highly mobile and able to grow, those in the FeCr alloys remained small and relatively motionless due to the pinning effect of the chromium.
Issue Date:2011-05-25
Rights Information:Copyright 2011 Carolyn Anne Tomchik.
Date Available in IDEALS:2011-05-25
Date Deposited:2011-05

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