Exploring mass transfer mechanisms in sintering processes through molecular dynamics simulation

Abstract

Molecular dynamics simulation was employed to delve into the mechanism of neck formation in a two-particle sintering model. Specifically, this study simulated the behavior of two nickel (Ni) nanoparticles, each with a diameter of 12 nanometers, utilizing the Embedded Atom Method (EAM) interatomic potential at a high temperature of 1200 K. Indeed, in this study, a meticulous examination of atom displacements enabled the evaluation of the neck formation mechanism through both qualitative and quantitative analyses. The qualitative assessments, encompassing forward and backward imaging techniques, indicated that diffusion and semi-convection were likely the most prominent mass transfer mechanisms during the sintering process of two nickel nanoparticles. For a quantitative analysis of the mass transfer mechanisms, Mean Square Displacement and Relative Mean Square Displacement were employed. The results of this analysis pertaining to neck formation revealed that the diffusion mechanism contributed to 17.6 % of the atomic displacement, with an associated magnitude of 2.7 Å. Furthermore, the analysis revealed that the contribution and average value of the semi-convection movement accounted for 82.4 % and 12.6 Å, respectively. Consequently, given the concurrent operation of both mass transfer mechanisms in this study, it becomes evident that semi-convection mass transfer can be established as the primary mechanism regulating the rate of neck formation.