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DY: Fachverband Dynamik und Statistische Physik

DY 31: Granular matter / contact dynamics II

DY 31.2: Vortrag

Freitag, 30. März 2007, 10:30–10:45, H2

Multiscale Simulations of Powder Sintering by Discrete Element Modeling — •Andreas Wonisch, Torsten Kraft, Michael Moseler, and Hermann Riedel — Fraunhofer Institute for Mechanics of Materials, Freiburg, Germany

In powder technology bulk materials are created from a huge number of particles that are first compacted and then bonded together by sintering. Sintering is activated by heating the powder at a high temperature below the melting point and leads to densification and grain growth. The driving force for this phenomenon is the surface energy of the grains. In order to better understand how the structure and dynamics on the grain scale affect macroscopic sintering behavior the discrete element method (DEM) is applied. The simulation scheme is based on a (random) aggregate of particles and takes mesoscopic properties like particle sizes, particle distribution, rotation and rearrangement into account. Appropriate pair forces between particles have been derived to simulate solid-state and liquid-state sintering where an additional liquid phase enhances the densification rate by rearrangement of grains. We show how rearrangement and rotation affects macroscopic sintering properties like densification rate and viscosity. We also demonstrate that certain kinds of particle configurations and boundary conditions lead to crack formation and anisotropic sintering behavior.