Processing model for tungsten powders and extension to nanoscale size range

Abstract

Nanoscale tungsten powders promise access to very hard, strong and wear resistant materials via the press–sinter route. A small particle size changes the response during sintering, requiring lower temperatures and shorter times to attain dense but small grain size structures. On the other hand, oxide reduction and impurity evaporation favour high sintering temperatures and long hold times. Accordingly, press–sinter processing encounters conflicting constraints when applied to small particles. Presented here is an analysis of press–sinter tungsten particle processing to isolate conditions that balance the temperature and size dependent effects. The calculations are pinned by existing data. Opportunities are identified for new consolidation approaches to deliver a small grain size in a full density structure.

Keywords:

• TUNGSTEN
• NANOSCALE
• SINTERING
• COMPACTION
• POWDER METALLURGY