Ultrahigh Strength in Nanocrystalline Materials Under Shock Loading
Eduardo M. Bringa,1*
Alfredo Caro,1
Yinmin Wang,1
Maximo Victoria,1
James M. McNaney,1
Bruce A. Remington,1
Raymond F. Smith,1
Ben R. Torralva,1
Helena Van Swygenhoven2
Molecular dynamics simulations of nanocrystalline copper under
shock loading show an unexpected ultrahigh strength behind the
shock front, with values up to twice those at low pressure.
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-based
plasticity and grain boundary sliding. These simulations, together
with new shock experiments on nanocrystalline nickel, raise
the possibility of achieving ultrahard materials during and
after shock loading.
2 Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland.
* To whom correspondence should be addressed. E-mail: ebringa{at}llnl.gov
