TITLE:

MODELING OF SINTERING PROCESSES – CURRENT DEVELOPMENTS

DATE:

Friday, September 28th, 2007

TIME:

3:30 PM

LOCATION:

GMCS 214

SPEAKER:

Eugene Olevsky, Department of Mechanical Engineering, San Diego State University

ABSTRACT:

Directions of further developments in the modeling of sintering will be pointed out with a special emphasis on multi-scale simulations and modeling of field-assisted sintering. The continuum theory of sintering enables computer models to predict shape changes and density evolution during the sintering process; the multi-scale extension of this theory can provide the full-fledged virtual reality of powder materials’ manufacturing. Various examples of the application of the multi-scale sintering modeling will be demonstrated including the analysis of the consolidation of powder electronic components, bio-materials fabrication, automotive and aircraft components’ production, etc. A novel continuum theory of sintering – based approach is applied to model the electric-field assisted – “spark-plasma” sintering (SPS) which involves rapid heating of powder by electric current with simultaneous application of an external pressure. Numerous experimental investigations point to the ability of SPS to render highly-dense powder products with the potential of grain size retention.
The latter ability is of significance for the consolidation of nano-powder materials where the grain growth is one of the major problems. Due to the complex nature of various phenomena involved in SPS, only few modeling attempts have been undertaken until presently. The conducted theoretical studies are mostly reduced to the modeling of temperature and electric current density distributions. A model for spark-plasma sintering (SPS) taking into consideration various mechanisms of material transport will be discussed. The contributions of sintering stress (surface tension), external load, and electromigration / ionic conduction to sintering shrinkage will be jointly analyzed. The results of modeling will be compared with the experimental data on the SPS shrinkage kinetics.

HOST:

Jose Castillo

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