Multiscale analysis of nano-powder compaction process using the FEM–MD technique

Abstract

In this paper, a continuum–atomistic (FEM–MD) multiscale technique is developed for modeling the compaction process of metallic nano-powders. Nano-powders are assumed as the continuum body that are modeled using the nonlinear finite element method (FEM). Representative volume element (RVE) consists of a number of nanoparticles to reflect the discrete nature of nano-powders. The atomistic RVEs are modeled using the molecular dynamics (MD) method to capture the plastic deformation of nanoparticles under the compaction process. The MD analysis of atomistic RVEs provides the feasibility of modeling the friction and interaction of nanoparticles. A parametric study is performed over the atomistic RVEs to evaluate the influence of various parameters, such as the type of boundary conditions, width of boundary layer, size and number of nanoparticles, and compaction velocity on the densification behavior of nano-powders. The effect of die-wall friction is investigated on the compaction behavior of nano-powders by evolution of die-wall friction coefficient for different values of compaction velocity and temperature. The accuracy of multiscale analysis is verified by comparing the numerical results with those of experimental data for the uniaxial compaction test. The performance of proposed computational method is finally presented in modeling the micro-cylindrical bush and micro-tablet components during the compaction process of micro-scale metallic nano-powders.