Temperature sensitivity of void nucleation and growth parameters for single crystal copper: a molecular dynamics study

The effect of temperature on the void nucleation and growth is studied using the molecular dynamics (MD) code LAMMPS(Large-Scale Atomic/Molecular Massively Parallel Simulator). Single crystal copper is triaxially expanded at 5 x 10(9) s(-1) strain rate keeping the temperature constant. It is shown that the nucleation and growth of voids at these atomistic scales follows a macroscopic nucleation and growth (NAG) model. As the temperature increases there is a steady decrease in the nucleation and growth thresholds. As the melting point of copper is approached, a double-dip in the pressure-time profile is observed. Analysis of this double-dip shows that the first minimum corresponds to the disappearance of the long-range order due to the creation of stacking faults and the system no longer has a FCC structure. There is no nucleation of voids at this juncture. The second minimum corresponds to the nucleation and incipient growth of voids. We present the sensitivity of NAG parameters to temperature and the analysis of double-dip in the pressure-time profile for single crystal copper at 1250 K.