Void configuration-induced change in microstructure and deformation mechanisms of nano-porous materials

Abstract

Void configuration plays an essential role in the deformation behavior of ductile metals; its effects on intervoid interference has not been investigated systematically until now. In the present study, molecular dynamics simulation was employed to study the void configuration-induced change in mechanical properties and deformation mechanisms during tensile loading. The results show that void configuration has a significant influence on the yield stress and yield strain, while its effect on the elastic modulus is about 3.14 ± 0.23%. The deformation mechanisms of porous materials with various void configurations at micro- and nanoscale are proposed: (i) local plastic deformation and (ii) homogeneous plastic deformation. Further analysis indicates that the difference between the above two deformation mechanisms is mainly caused by the competition and synergy between the stacking faults and dislocation. Local plastic deformation is mainly controlled by stacking faults. Homogeneous plastic deformation is dominated by dislocation motion with only a small amount of stacking shear motion, which gives material a superior plastic elongation. The result is of great value for improving the plasticity limit of nanostructures.