Cooperative processes during plastic deformation in nanocrystalline fcc metals: A molecular dynamics simulation

Large scale molecular dynamics (MD) simulations are used to simulate the plastic deformation of a nanocrystalline model Ni sample with an average grain size of 5 nm containing 125 grains at 800 K up to 4.0% plastic strain. For the first time in MD simulation, emerging shear planes involving several grain boundaries have been observed indicating cooperative plastic deformation activity between grains. It is found that three mechanisms have been involved in the development of such shear planes: grain-boundary migration, continuity of shear plane via intragranular slip, and rotation and coalescence of grains.