Mapping the compaction and sintering response of tungsten-based materials into the nanoscale size range

Considerable knowledge exists on processing tungsten powders over a broad particle size range. Published data and processing models have been combined for tungsten powders ranging from 20 nm to 18 μm to build a response model for press-sinter processing. The model predicts apparent density, green density, green strength, sintered density, sintered grain size, and product properties such as strength, hardness, and wear resistance. Further, the model isolates several problems as particle size decreases that will require changes in how tungsten powders are handled, compacted, and sintered. Maps of strength versus processing conditions are generated from the model to direct future efforts toward improved properties using nanoscale tungsten powders. From these findings, new opportunities become evident for press-sinter consolidation of nanoscale powders.