Molecular-dynamic study of the size effect in the compacting of monodisperse aluminum nanopowder

With the help of molecular dynamics simulation, the influence of the dimensions of aluminum particles in the range of 6–24 nm on the dynamics of nanopowder compacting under deformation of the system with constant rate of 1/ns. It is shown that an increase in nanoparticle sizes from 6 to 12 nm leads to a drop in the yield strength of the nanopowder from 0.4 to 0.3 GPa, and a further increase in the size of the nanoparticles does not affect the yield strength. The density of the system at zero pressure, determined by the adhesion forces, decreases with increasing nanoparticle sizes from 6 to 12 nm, and then does not change. When the nanopowder is compressed, the main increase in density occurs with a pressure increase of up to 1–2 GPa, and complete collapse of the voids takes place as the pressure increases to 5.5 GPa. Increasing the size of nanoparticles leads to a slowing down of the compaction process.