Transition of dislocation glide to shear transformation in shocked tantalum
Abstract
A TEM study of pure tantalum and tantalum-tungsten alloys explosively shocked at a peak pressure of 30 GPa (strain rate: ~1 x 104 sec-1) is presented. While no ω (hexagonal) phase was found in shock-recovered pure Ta and Ta-5W that contain mainly a low-energy cellular dislocation structure, shock-induced ω phase was found to form in Ta-10W that contains evenly distributed dislocations with a stored dislocation density higher than 1 x 1012 cm-2. The TEM results clearly reveal that shock-induced α (bcc) → ω (hexagonal) shear transformation occurs when dynamic recovery reactions which lead the formation low-energy cellular dislocation structure become largely suppressed in Ta-10W shocked under dynamic (i.e., high strain-rate and high-pressure) conditions. A novel dislocation-based mechanism is proposed to rationalize the transition of dislocation glide to twinning and/or shear transformation in shock-deformed tantalum. Lastly, twinning and/or shear transformation take place as an alternative deformation mechanism to accommodate high-strain-rate straining when the shear stress required for dislocation multiplication exceeds the threshold shear stresses for twinning and/or shear transformation.
- Authors:
-
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Publication Date:
- Research Org.:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1347662
- Report Number(s):
- LLNL-JRNL-710038
Journal ID: ISSN 2059-8521; applab
- Grant/Contract Number:
- AC52-07NA27344
- Resource Type:
- Accepted Manuscript
- Journal Name:
- MRS Advances
- Additional Journal Information:
- Journal Volume: 2; Journal Issue: 27; Journal ID: ISSN 2059-8521
- Publisher:
- Materials Research Society (MRS)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE
Citation Formats
Hsiung, Luke L., and Campbell, Geoffrey H. Transition of dislocation glide to shear transformation in shocked tantalum. United States: N. p., 2017.
Web. doi:10.1557/adv.2017.236.
Hsiung, Luke L., & Campbell, Geoffrey H. Transition of dislocation glide to shear transformation in shocked tantalum. United States. https://doi.org/10.1557/adv.2017.236
Hsiung, Luke L., and Campbell, Geoffrey H. Tue .
"Transition of dislocation glide to shear transformation in shocked tantalum". United States. https://doi.org/10.1557/adv.2017.236. https://www.osti.gov/servlets/purl/1347662.
@article{osti_1347662,
title = {Transition of dislocation glide to shear transformation in shocked tantalum},
author = {Hsiung, Luke L. and Campbell, Geoffrey H.},
abstractNote = {A TEM study of pure tantalum and tantalum-tungsten alloys explosively shocked at a peak pressure of 30 GPa (strain rate: ~1 x 104 sec-1) is presented. While no ω (hexagonal) phase was found in shock-recovered pure Ta and Ta-5W that contain mainly a low-energy cellular dislocation structure, shock-induced ω phase was found to form in Ta-10W that contains evenly distributed dislocations with a stored dislocation density higher than 1 x 1012 cm-2. The TEM results clearly reveal that shock-induced α (bcc) → ω (hexagonal) shear transformation occurs when dynamic recovery reactions which lead the formation low-energy cellular dislocation structure become largely suppressed in Ta-10W shocked under dynamic (i.e., high strain-rate and high-pressure) conditions. A novel dislocation-based mechanism is proposed to rationalize the transition of dislocation glide to twinning and/or shear transformation in shock-deformed tantalum. Lastly, twinning and/or shear transformation take place as an alternative deformation mechanism to accommodate high-strain-rate straining when the shear stress required for dislocation multiplication exceeds the threshold shear stresses for twinning and/or shear transformation.},
doi = {10.1557/adv.2017.236},
journal = {MRS Advances},
number = 27,
volume = 2,
place = {United States},
year = {Tue Feb 28 00:00:00 EST 2017},
month = {Tue Feb 28 00:00:00 EST 2017}
}
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Works referencing / citing this record:
Understanding and predicting damage and failure at grain boundaries in BCC Ta
journal, October 2019
- Chen, J.; Hahn, E. N.; Dongare, A. M.
- Journal of Applied Physics, Vol. 126, Issue 16