Nonlinear elastic response of single crystal Cu under uniaxial loading by molecular dynamics study

Molecular dynamics simulations were carried out to study the mechanical response of single crystal Cu with various orientations under uniaxial loading. Cu shows a high degree of elastic anisotropy as a function of the crystal orientations, and the yield stress varies significantly with the crystal orientations and the loading directions. An obvious nonlinear stress-strain response was observed at the elastic deformation stage under applied loading, namely elastic hardening and elastic softening. This nonlinear elastic behavior is derived from the potential energy between atoms and can play a significant role in yield stress and yield asymmetry of crystals under tension and compression.