STP955

    A Composite Model of Microstructural Evolution in Austenitic Stainless Steel Under Fast Neutron Irradiation

    Published: Jan 1987


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    Abstract

    A rate-theory-based model has been developed which includes the simultaneous evolution of the dislocation and cavity components of the microstructure of irradiated austenitic stainless steels. Previous work has generally focused on developing models for void swelling while neglecting the time dependence of the dislocation structure. These models have broadened our understanding of the physical processes that give rise to swelling, for example, the role of helium and void formation from critically-sized bubbles. That work has also demonstrated some predictive capability by successful calibration to fit the results of fast reactor swelling data. However, considerable uncertainty about the values of key parameters in these models limits their usefulness as predictive tools. Hence, the use of such models to extrapolate fission reactor swelling data to fusion reactor conditions is compromised.

    The present work represents an effort to remove some of these uncertainties by self-consistently generating the time dependence of the dislocation structure, both faulted loops and network dislocations. The model's predictions reveal the closely coupled nature of the evolution of the various microstructural components and generally track the available fast reactor data in the temperature range of 350 to 700°C for doses up to 100 dpa. As the theoretical model has become more complex, parameter choices were constrained to a more limited range of values in order to obtain this agreement between theory and experiment. While the model remains approximate in many respects, it should ultimately provide a more useful tool for understanding microstructural evolution under irradiation and permit more confident predictions of void swelling in future fusion reactors.

    Keywords:

    cavity evolution, dislocation evolution, microstructural evolution, rate theory, stainless steels, theoretical models, void swelling


    Author Information:

    Stoller, RE
    Research staff member, Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN

    Odette, GR
    Professor, University of California, Santa Barbara, CA


    Paper ID: STP33831S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP33831S


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