Sintering of small particles

Abstract

An atomistic approach to modeling the sintering of nanocrystalline alloys has been developed. It has been shown that there exist alloys that exhibit both nanostructured stability and undergo an accelerated sintering process [1], [2]. However, the widespread adoption of such alloys has been limited by a lack of understanding of the processing kinetics that lead to the accelerated sintering phenomena. To better understand the role of surface diffusion, and the effect that system enthalpies of mixing have on inter-particle neck formation, a 3D kinetic monte carlo (KMC) model was proposed to study these phenomena. The results of these simulations demonstrate that positive enthalpy of mixing highlighted as a necessary criterion for nanocrystalline stability in [1], also leads to the fast diffusing elements ability to form the interparticle neck. The condition of lower temperature neck formation by fast diffusing alloy elements is hypothesized to be the mechanism behind which accelerated sintering occurs. The findings in this paper demonstrate that positive enthalpy of mixing alloys can be designed to sinter at lower temperatures and shorter cycle durations if they have adequate solute present on the surface of the particle.