PLASTIC BEHAVIOR OF NANOPHASE NI - A MOLECULAR-DYNAMICS COMPUTER-SIMULATION

We report molecular dynamics computer simulations of low temperature-h igh load plastic deformation of Ni nanophase samples with several mean grain sizes in the range of 3-5 nm. The samples are polycrystals nucl eated from different seeds, with random location and orientation. Amon g the mechanisms responsible for the deformation, grain boundary slidi ng and motion, as well as grain rotation are identified. No dislocatio n activity is detected, in contrast to the behavior of coarse grain me tals. Interpreting the results in terms of grain boundary viscosity, a linear dependence of strain rate with the inverse of the grain size i s obtained. (C) 1997 American Institute of Physics.