STP1505: Role of Twinning and Slip in Deformation of a Zr-2.5Nb Tube

    Kim, Young S.
    Korea Atomic Energy Research Institute, Daejeon,

    Pages: 17    Published: Jan 2009


    Abstract

    Tensile tests were conducted from RT to 400°C on tensile specimens taken from the tangential direction (TD) and the longitudinal direction (LD) of a Zr-2.5Nb tube with a strong tangential texture. When tensile stresses were applied to the TD with the tensile axis normal to the basal plane, {1012} twinning was activated. With the tensile stresses applied to the LD, however, ‹a› slip only was activated. The activation of twinning and slip in the TD and the LD, respectively, caused the tensile properties of the Zr-2.5Nb tube to become anisotropic, leading to higher yield and tensile strengths, and lower uniform and tensile elongations in the TD when compared to those in the LD. Furthermore, twinning promoted softening soon after yielding only in the TD, and localized deformation, while the ‹a› slip on the prism plane caused a larger strain hardening after yielding. With increasing temperature, the primary deformation mode changed from twinning to ‹c+a› slip in the TD and ‹a› slip to ‹c+a› slip in the LD, resulting in negative temperature dependences for the extent of strain hardening and tensile elongation of the Zr-2.5Nb tube in both directions. The yield stress plateau is discussed in view of the activation of twinning or ‹c+a› slip with a higher critical resolved shear stress that is strongly temperature dependent.


    Paper ID: STP48139S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP48139S


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