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Mechanical Behavior of Ta at Extreme Strain-Rates

  • Daniel CasemEmail author
  • Daniel Magagnosc
  • Jonathan Ligda
  • Brian Schuster
  • Timothy Walter
Conference paper
Part of the Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)

Abstract

The compressive stress-strain response of a commercially pure (99.98%) Ta was investigated at strain-rates ranging from 0.001/s to 500 k/s. Strain-rates up to 20 k/s were obtained using conventional load frames and Kolsky bar methods. The higher strain-rates were obtained using optically instrumented miniature Kolsky bars. Because these experiments require sample sizes as small as ∼30 um, a fine grain structure was desired. To achieve this, we study a Ta billet that was processed by ECAE to produce an ultrafine grain structure. The billets were subsequently annealed at 1203 K under high vacuum for 2 h to coarsen the grain size to approximately 2 um. The as-worked and annealed microstructures were investigated by electron backscatter diffraction to verify the grain structure. A strong rate dependence is observed over this range of strain-rates, although there is a discrepancy between data at similar strain-rates using different sample sizes. This discrepancy is the subject of on-going investigation.

Keywords

Tantalum Split Hopkinson pressure bar Kolsky bar High strain-rate Plasticity 

Notes

Acknowledgements

The authors would like to thank Mr. Kevin Taylor for his help conducting the low-rate experiments and for preparing the samples.

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Copyright information

© The Society for Experimental Mechanics, Inc. 2019

Authors and Affiliations

  • Daniel Casem
    • 1
    Email author
  • Daniel Magagnosc
    • 2
  • Jonathan Ligda
    • 2
  • Brian Schuster
    • 3
  • Timothy Walter
    • 2
  1. 1.RDRL-WMP-C, US Army Research Laboratory, Aberdeen Proving GroundAberdeenUSA
  2. 2.RDRL-WMM-B, US Army Research Laboratory, Aberdeen Proving GroundAberdeenUSA
  3. 3.RDRL-WML-H, US Army Research Laboratory, Aberdeen Proving GroundAberdeenUSA

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