Dynamic shock studies of vanadium

Conference · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5415646

Chhabildas, L C; Hills, C R

Using gas-gun loading techniques and velocity interferometric techniques, time-resolved wave profiles have been obtained in vanadium over the stress range of 2.9 to 9.7 GPa. The risetime data indicate steepened shock structures with increasing shock amplitude. However, unlike aluminum, finite risetimes are determined even at 9.7 GPa, indicating a large effective viscosity for the material. The dynamic yield strength measured at the Hugoniot elastic limit is 0.8 GPa and is approximately twice the static yield strength. Material softening is evidenced through measurements of shock velocity and yield strength determinations in the shocked state. The yield strength of the material upon release from the shocked state is estimated to be approx.0.43 GPa and is comparable to the static yield strength. Strain-rate dependent processes may be responsible for a higher elastic shear stress sustained before relaxation to an equilibrium value. The primary mode of deformation in shocked vanadium appears to be cross slip, resulting in dislocation tangles. Deformation twins are also observed in shock-recovered specimens with an increasing number with increased shock stress. The thermal diffusivity for vanadium is low, and the shear-strength loss observed in this material is consistent with the strength loss observed for other materials which also have low thermal diffusivities. It is conceivable that the loss of shear strength may be due to long thermal recovery times resulting from inhomogeneous deformation process.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5415646
• Report Number(s): SAND-85-0322C; CONF-850770-7; ON: DE85017381
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
CRYSTAL STRUCTURE
DEFORMATION
DYNAMIC LOADS
ELECTRON MICROSCOPY
ELEMENTS
HARDNESS
MECHANICAL PROPERTIES
METALS
MICROSCOPY
MICROSTRUCTURE
SHOCK WAVES
TRANSITION ELEMENTS
TRANSMISSION ELECTRON MICROSCOPY
VANADIUM
YIELD STRENGTH