ULTRA-HIGH STRENGTH IN NANOCRYSTALLINE MATERIALS UNDER SHOCK LOADING

Journal Article · Mon Apr 11 04:00:00 EDT 2005 · Science

OSTI ID:877886

Bringa, E M; Caro, A; Wang, Y M; Victoria, M; McNaney, J; Remington, B A; Smith, R; Torralva, B; Van Swygenhoven, H

Molecular dynamics simulations of nanocrystalline (nc) copper under shock loading show an unexpected ultra-high strength behind the shock front. The strength at high pressure can be up to twice the value at low pressure, for all grain sizes studied here (5-50 nm grains, with up to {approx}4 10{sup 8} atoms). Partial and perfect dislocations, twinning, and debris from dislocation interactions are found behind the shock front. Results are interpreted in terms of the pressure dependence of both deformation mechanisms active at these grain sizes, namely dislocation plasticity and grain boundary sliding. These simulations, together with new shock experiments on nc nickel, raise the possibility of achieving ultra-hard materials during and after shock loading.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 877886
• Report Number(s): UCRL-JRNL-211450
• Journal Information: Science, Journal Name: Science Vol. 309; ISSN 0193-4511; ISSN SCEHDK
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMS
COPPER
DEFORMATION
DISLOCATIONS
GRAIN SIZE
NICKEL
PLASTICITY
PRESSURE DEPENDENCE
TWINNING