Shock compression and quasielastic release in tantalum
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Previous studies of quasielastic release in shock-loaded FCC metals have shown a strong influence of the defect state on the leading edge, or first observable arrival, of the release wave. This is due to the large density of pinned dislocation segments behind the shock front, their relatively large pinning separation, and a very short response time as determined by the drag coefficient in the shock-compressed state. This effect is entirely equivalent to problems associated with elastic moduli determination using ultrasonic methods. This is particularly true for FCC metals, which have an especially low Peierls stress, or inherent lattice resistance, that has little influence in pinning dislocation segments and inhibiting anelastic deformation. BCC metals, on the other hand, have a large Peierls stress that essentially holds dislocation segments in place at low net applied shear stresses and thus allows fully elastic deformation to occur in the complete absence of anelastic behavior. Shock-compression and release experiments have been performed on tantalum (BCC), with the observation that the leading release disturbance is indeed elastic. This conclusion is established by examination of experimental VISAR records taken at the tantalum/sapphire (window) interface in a symmetric-impact experiment which subjects the sample to a peak longitudinal stress of approximately 7.3 GPa, in comparison with characteristic code calculations. [copyright] 1994 American Institute of Physics
- OSTI ID:
- 6929680
- Report Number(s):
- CONF-921145--
- Journal Information:
- AIP Conference Proceedings (American Institute of Physics); (United States), Journal Name: AIP Conference Proceedings (American Institute of Physics); (United States) Vol. 309:1; ISSN APCPCS; ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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Shock compression and quasielastic release in tantalum
Anelastic release from the shock-compressed state
Related Subjects
360103* -- Metals & Alloys-- Mechanical Properties
ALUMINIUM
BCC LATTICES
COMPRESSION
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DISLOCATIONS
ELEMENTS
IMPACT SHOCK
LINE DEFECTS
METALS
RELAXATION
SHOCK WAVES
STRESS RELAXATION
TANTALUM
TRANSITION ELEMENTS
VERY HIGH PRESSURE
WAVE FORMS