The structure of controlled shear bands in dynamically deformed reactive mixtures

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Metallurgical Transactions, A

DOI:https://doi.org/10.1007/BF02669409· OSTI ID:131432

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

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1. Univ. of California, San Diego, CA (United States)

The structures of controlled high-strain-rate shear bands generated in heterogeneous reactive porous materials (Nb + Si, Mo + Si + MoSi{sub 2}) has been investigated using axially symmetric experimental configurations in which the source of energy is the detonation of low velocity explosives. The deformation was highly localized, with profuse formation of shear bands, which have thicknesses of 5 to 20 {micro}m. The experimental method generated overall strains up to 100 and strain rates {dot {gamma}} of approximately 10{sup 7} s{sup {minus}1}. Changes in particle morphology, melting, and regions of partial reaction on three different length scales were observed. The shear band thickness is smaller than the initial characteristic particle size of the porous mixture ({le}44 {micro}m), ensuring a cooling time of the deformed material on the same order of magnitude as the deformation time (10{sup {minus}5}s). In the shear localization regions, two characteristic phenomena were observed: (a) a shear fracture subdividing the Nb particles into thin parallel layers and (b) the formation of vortices. A mechanism for the reaction inside the shear bands is proposed, and an expression for the largest size of chemical products as a function of shear deformation is obtained.

• Sponsoring Organization: USDOE
• OSTI ID: 131432
• Journal Information: Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 10 Vol. 26; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
CHEMICAL REACTIONS
DEFORMATION
EXPLOSIVES
FRACTURES
INTERMETALLIC COMPOUNDS
MICROSTRUCTURE
MOLYBDENUM
MOLYBDENUM SILICIDES
NIOBIUM
PARTICLE SIZE
POWDERS
SHOCK WAVES
SILICON
STRAIN RATE
STRAINS
VORTICES