LASER COMPRESSION OF NANOCRYSTALLINE METALS

Journal Article · Mon Dec 28 00:00:00 EST 2009 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3294981· OSTI ID:21366833

Meyers, M A; Jarmakani, H N ^[1]; Bringa, E M; Earhart, P; Remington, B A ^[2]; Vo, N Q; Wang, Y M ^[3]

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1. University of California, San Diego, La Jolla, CA 92093-0418 (United States)
2. Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)
3. University of Illinois, Urbana-Champaign, Urbana, IL 61801 (United States)

Shock compression in nanocrystalline nickel is simulated over a range of pressures (10-80 GPa) and compared with experimental results. Laser compression carried out at Omega and Janus yields new information on the deformation mechanisms of nanocrystalline Ni. Although conventional deformation does not produce hardening, the extreme regime imparted by laser compression generates an increase in hardness, attributed to the residual dislocations observed in the structure by TEM. An analytical model is applied to predict the critical pressure for the onset of twinning in nanocrystalline nickel. The slip-twinning transition pressure is shifted from 20 GPa, for polycrystalline Ni, to 80 GPa, for Ni with g. s. of 10 nm. Contributions to the net strain from the different mechanisms of plastic deformation (partials, perfect dislocations, twinning, and grain boundary shear) were quantified in the nanocrystalline samples through MD calculations. The effect of release, a phenomenon often neglected in MD simulations, on dislocation behavior was established. A large fraction of the dislocations generated at the front are annihilated.

• OSTI ID: 21366833
• Journal Information: AIP Conference Proceedings, Vol. 1195, Issue 1; Conference: American Physical Society Topical Group on shock compression of condensed matter, Nashville, TN (United States), 28 Jun - 3 Jul 2009; Other Information: DOI: 10.1063/1.3294981; (c) 2009 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPRESSION
CRITICAL PRESSURE
DEFORMATION
DISLOCATIONS
GRAIN BOUNDARIES
HARDENING
HARDNESS
LASERS
MOLECULAR DYNAMICS METHOD
NANOSTRUCTURES
NICKEL
PLASTICITY
POLYCRYSTALS
PRESSURE RANGE GIGA PA
SHOCK WAVES
SIMULATION
TRANSMISSION ELECTRON MICROSCOPY
TWINNING
CALCULATION METHODS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
ELECTRON MICROSCOPY
ELEMENTS
LINE DEFECTS
MECHANICAL PROPERTIES
METALS
MICROSCOPY
MICROSTRUCTURE
PHYSICAL PROPERTIES
PRESSURE RANGE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS