Effect of strain rate and dislocation density on the twinning behavior in Tantalum

ORAL

Abstract

Compression experiments on polycrystalline Ta were conducted at liquid nitrogen temperatures at stain rates ranging from 10$^{-4 }$to 10$^{5}$ s$^{-1}$. In addition, samples were cold-rolled and then tested at liquid nitrogen temperatures to determine the effect of dislocation density on the overall twin fraction. Samples were also pre-strained to induce a range of dislocation densities to see the effect of the initial density on the amount of twinning observed. Recovered samples were characterized using EBSD orientation mapping along with transmission electron microscopy to assess the occurrence of twinning under each test condition.

*This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

–

Authors

  • Jeff Florando

    • Lawrence Livermore National Laboratory
    • Lawrence Livermore National Lab

  • James McNaney

    • Lawrence Livermore National Laboratory

  • Mary LeBlanc

    • Lawrence Livermore National Laboratory

  • Mukul Kumar

    • Lawrence Livermore National Laboratory

  • Changqiang Chen

    • Johns Hopkins University

  • Kaliat Ramesh

    • Johns Hopkins University

  • Kevin Hemker

    • Johns Hopkins University