Shear localization in granular alumina under high-strain-rate deformation

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:175195

Meyers, M A; Chen, H C ^[1]; Nesterenko, V F ^[2]

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1. Univ. of California, San Diego, La Jolla, CA (United States)
2. Institute of Hydrodynamics, Novosibirsk (Russian Federation)

Dynamic deformation of densified granular alumina of two different particle sizes (< 0.5 {mu}m and < 5 {mu}m) was investigated by the {open_quotes}Thick-Walled Cylinder{close_quotes} method. Shear localization was the main deformation mode at an overall radial strain of {approximately}0.2 and strain rate of 10{sup 4} sec{sup -1}. The following qualitative features of shear bands were established: (1) Shear band thickness does not depend on particle size and has a typical value {approximately}10 {mu}m. (2) The structure of the shear bands was dependent on initial particle size, suggesting that the mechanisms of flow were different; for the < 5 {mu}m particles, comminutum (break-up) and softening of particles were observed. For the < 0.5 {mu}m particles, a peculiar structure consisting of a central crack with two lateral cracks was formed. (3) Distributions of shear bands and displacement magnitudes are dependent on initial particle sizes. The difference in alumina behavior is connected with partial fracturing of large particles under shear deformation. This results in their repacking and subsequent material hardening during shear deformation, retarding the beginning of shear localization in alumina with large particles. Simple physical models will be presented.

• OSTI ID: 175195
• Report Number(s): CONF-950686--; CNN: Contract DAAH 04-94-G-031; Contract N00014-94-1-1040
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CRACKS
DEFORMATION
PARTICLE SIZE
SHEAR
STRAIN RATE