Pressure effects on grain boundary plasticity in nanophase metals

Grain boundary sliding is often the picture that explains computer simulation results and experiments on plasticity of nanophase materials. Using atomistic computer simulations we perform a detailed study of the effects, of high hydrostatic pressure on nanophase Cu plasticity and find that it can be understood in terms of pressure dependent grain boundary sliding controlled by a Mohr-Coulomb law. This result explains recent findings on pressure-induced ultrahigh strength observed in computer simulations of shocks in nanophase Cu reported by Bringa et al. [Science 309, 1838 (2005)]. (c) 2006 American Institute of Physics.