Dominant mechanisms of the sintering of copper nano-powders depending on the crystal misalignment

Sintering mechanisms of nanoscale copper powder are investigated using molecular dynamics ( MD) simulations based on the embedded-atom method (EAM). The densification parameters, such as shrinkage, and relative sintered density are calculated using the two-particle sintering model. This paper considers the important role of crystalline misalignment between two particles on densification. Besides volume diffusion contribution, misalignment between the crystal structures results in enhanced grain boundary diffusion. At low temperatures, grain boundary torque cause particles to rotate to reduce grain boundary energy. At higher temperatures, particle rotation becomes complicated including remarkable twist, and grain boundary tilting due to grain-boundary-like diffusion. These results provide insights to the processing cycle parameters applicable to nano-powders. (C) 2016 Elsevier B.V. All rights reserved.