In situ transmission electron microscopy ion irradiations of model iron-chromium alloys

Tomchik, Carolyn A.

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https://hdl.handle.net/2142/24322 Copy

Description

Title

In situ transmission electron microscopy ion irradiations of model iron-chromium alloys

Author(s)

Tomchik, Carolyn A.

Issue Date

2011-05-25T15:03:55Z

Director of Research (if dissertation) or Advisor (if thesis)

Stubbins, James F.

Department of Study

Nuclear, Plasma, & Rad Engr

Discipline

Nuclear Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(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.

Graduation Semester

2011-05

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http://hdl.handle.net/2142/24322

Copyright and License Information

Copyright 2011 Carolyn Anne Tomchik.

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