Sintering processes of two nanoparticles: A study by molecular-dynamics

Molecular-dynamics computer simulations were employed to investigate the mechanisms of sintering of two single-crystal nanoparticles of Cu at a temperature of 700 K. Owing to their ultra-fine size (4.8 nm in diameter), the local shear stresses in the necks were sufficiently large to induce plastic deformation and densification. For both aligned and randomly oriented spheres, dislocations formed in the neck glided on the normal slip system of fee Cu to the surface. The misaligned particles rotated about 17 degrees relative to each other during deformation and formed a low-energy boundary. For the aligned nanoparticles, deformation occurred by glide of screw dislocations, but without rotation.