Large scale molecular dynamics simulations are aimed at understanding the micromechanisms of nucleation, coalescence, and growth of voids in nanocrystalline metals (Cu, Al). Current focus is on systems with grain sizes between 2 nm to 15 nm for strain rates > 10^7 /s. Voids nucleate at grain boundary junctions and grow by the shearing of neighboring atoms. Void growth is accompanied by the formation of a disordered region surrounding the void which later recrystallizes due to the increase in temperature associated with the plastic deformation. The snapshots of a section of the system at (a) 362 ps, (b) 366 ps, (c) 370 ps, (d) 374 ps, (e) 390 ps, and (f) 400 ps, showing the growth of the void under conditions of uniaxial tensile strain at a constant strain rate of 10^8 s-1. The atoms are colored using common neighbor analysis.  [Phys Rev B 80, 104108 (2009)]