Mechanical characteristics of die-wall friction on the compaction process of metal nano-powders

• Published in: Powder technology 2024-08, Vol.444, p.119987, Article 119987
• Main Authors: Khoei, A.R., Sameti, A. Rezaei, Kazempour, Z., Pourkermani, A. Ghafouri
• Format: Article
• Language: English
• Subjects: Compaction process; Die-wall friction coefficient; MD analysis; Nano-powders
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2024.119987

The die-wall friction is one of the influential mechanical factors in the metal nano-powder compaction process that can noticeably impress the densification behavior of nanoparticles. In this study, the uniaxial cold compaction process of aluminum nano-powders, which are initially loaded into the nickel die-walls, is analyzed using the molecular dynamics (MD) method. The influence of die-wall friction is studied on the nano-powder compaction process. The results illustrate the effect of frictional die-walls on the characteristics of relative density–pressure and stress–strain curves, the pressure distribution of nano-powders, and the final green product. The evolution of the die-wall friction coefficient on the compaction velocity and temperature is determined during the compaction process. Applying the nonlinear regression method, an empirical relation is derived to estimate the frictional behavior of die-walls at different relative densities. It is demonstrated that the proposed computational model has acceptable accuracy to evaluate the die-wall friction during the nano-powder compaction process. [Display omitted] •Influence of die-wall friction on the compaction process of aluminum nano-powders,•Dependence of die-wall friction on the density–pressure and stress–strain curves,•Evolution of friction coefficient at various compaction velocities and temperatures,•An empirical relation for die-wall friction during nano-powder compaction process.