STP1492

    Strain Hardening During Mechanical Twinning and Dislocation Channeling in Irradiated 316 Stainless Steels

    Published: Jan 2008


      Format Pages Price  
    PDF (472K) 13 $25   ADD TO CART
    Complete Source PDF (11M) 13 $74   ADD TO CART


    Abstract

    Localized deformation mechanisms and strain-hardening behaviors in irradiated 316 and 316LN stainless steels were investigated, and a theoretical model was proposed to explain the linear strain-hardening behavior during the localized deformation. After low temperature irradiation to significant doses, the deformation microstructure changed from dislocation tangles to channels or mechanical twins. It was also observed that irradiation hardening straightened gliding dislocations and increased the tendency for forming pileups. Regardless of these microstructural changes, the strain-hardening behavior was relatively insensitive to the irradiation. This dose-independent strain-hardening rate resulted in dose independence of the true stress parameters, such as the plastic instability stress and true fracture stress. In the proposed model, the long-range back stress was formulated as a function of the number of pileup dislocations per slip band and the number of slip bands in a grain. The calculation results confirmed the experimental observation that strain-hardening rate was insensitive to the change in deformation mechanism because the long-range back stress hardening became as high as the hardening by tangled dislocations.

    Keywords:

    radiation effect, strain-hardening behavior, strain localization, dislocation channels, mechanical twins, long-range back stress, pileup dislocations


    Author Information:

    Byun, T. S.
    Oak Ridge National Laboratory, Oak Ridge, TN

    Hashimoto, N.
    Oak Ridge National Laboratory, Oak Ridge, TN


    Paper ID: STP46568S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP46568S


    CrossRef ASTM International is a member of CrossRef.