Strength predictions for bulk structures fabricated from nanoscale tungsten powders

In concept, nanoscale tungsten powders should enable the production of very hard, strong, and wear-resistant sintered tungsten alloys and compounds. However, data from the press-sinter processing of small tungsten powders generally do not provide the anticipated property gains. Accordingly, existing press-sinter data from a range of tungsten particle sizes are used to formulate a model relevant to nanoscale powders. The model includes both size-dependent and temperature-dependent aspects. Available data are used to train the model to allow calculations of the sintered strength for various powders and processing cycles. Model predictions for density, grain size, sintered hardness, and sintered strength are used to isolate new processing strategies customized to nanoscale powders. Preservation of the nanoscale microstructure requires considerable departure from standard powder handling practices and fabrication cycles.