Multiscale model of sintering: diffusion and plastic flow

Impacting particles or static aggregated particles at high temperature may undergo a
permanent change of shape modifying the microstructure. Two particles in contact can develop
some bonds within sub-second time. This fast sintering force in the particular case of the snow
contribute to the rheological behavior and grain rearrangement [1]. Understanding the kinetics
of sintering in granular material is of great importance in some engineering applications.
For decades, diffusional processes have received more attention in investigations related to the
mechanisms behind sintering [2]. Some works have suggested that the plastic flow might be
neglected in sintering process for stresses are not high enough to cause dislocation. However,
some studies have showed that stresses experienced in fine particles necks can be high enough
and even lead to plasticity driven sintering. The importance of each mechanism in the sintering
process may lie in the temporal and spatial scale of interest.
Increasing importance is being accorded to the role of plastic flow in sintering. however,
several investigations have proved that the conventional plasticity theory may fail to predict
plastic activity at micro-scale,
The objective of this work is to develop adequate computational model that includes
instantaneous and time-dependent plastic flow at micro-scale. We aim at extending existing
models of sintering and plasticity to cope with multiple spatial and temporal scales simulations
using Extended Discrete Element Method. The numerical results are compare to experimental
data on snow.