Deformation and localized necking mechanism of nanocrystalline materials by molecular dynamics simulation (relationship between intergranular deformation and intragranular deformation of nanocrystalline materials)

Abstract

We examine the deformation and localized necking mechanism of round bar specimen of nanocrystalline materials by molecular dynamics simulation, and consider the relationship between the intergranular deformation and the intragranular deformation of nanocrystalline materials. We use two atomic interaction potentials which show different values of stacking fault energy. In the case of high stacking fault energy, the model is deformed by mainly the intergranular deformation; grain boundary sliding, and a little intragranular deformation; crystal slips by the movement of perfect dislocation, but in contrast, in the case of low stacking fault energy, the deformation is caused by the intragranular deformation by the movement of partial dislocation that leaves stacking fault plane in grains. Because stacking fault planes in grains prevent the activation of other slip systems, a kind of work hardening-like effect is observed.