Compaction simulation of crystalline nano-powders under cold compaction process with molecular dynamics analysis

AR Khoei and AR Sameti and H Mofatteh, POWDER TECHNOLOGY, 373, 741-753 (2020).

DOI: 10.1016/j.powtec.2020.06.069

In this paper, the uniaxial cold compaction process of metal nano- powders is numerically analyzed through the Molecular Dynamics (MD) method. The nano-powders consist of nickel and aluminum nano-particles in the pure and mixed forms with distinctive contributions. The numerical simulation is performed using the different number of nano- particles, mixing ratios of Ni and Al nano-particles, compaction velocities, and ambient temperatures in the canonical ensemble until the full-dense condition is achieved. In the MD analysis, the inter-atomic interaction between metal nano-particles is modeled by the many-body EAM potential, and the interaction between frictionless rigid die-walls and metal nano-particles is modeled by the pairwise Lennard-Jones inter- atomic potential. The mechanical behavior of metal nano-powders under the compaction process is numerically studied by plotting the relative density-pressure, mean stress-strain, and material characteristics- strain curves. Moreover, the nano-powder behavior is visualized by means of the centro-symmetry contour at various stages of the forming process. Finally, the evolution of top-punch velocity on the final stage of compaction process is studied by plotting the compaction pressure against the total energy at various compaction velocities. (C) 2020 Elsevier B.V. All rights reserved.

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