This document describes a tungsten heavy alloy powder comprising pre-alloyed, dense and spherical particles with a patent pending. The powder has several general features including a fully developed metal matrix microstructure, flexible particle size distribution between 10 μm and upwards, and tap densities between 60-80% volume. The powder is conceived to be used for hot isostatic pressing, additive manufacturing, metal injection molding, and other applications due to its high density and sintering properties compared to pure tungsten powder. It is proposed that the powder could enable powder-based hot isostatic pressing of large tungsten heavy alloy parts with improved properties.

1. Tungsten heavy alloy powder
comprising
pre-alloyed, dense & spherical
particles
Patent pending, Maxwha AB

2. General features
• pre-alloyed particles
• fully developed metal matrix
composite microstructure
• Spherical particles
• Flexible particle size distribution: +10 µm-range
• TAP-densities in the range of 60 to 80 vol-%
• Up to about 14 g/cm3 for 97W-grades
Cross-section

3. Conceived applications
1. Powder for Hot Isostatic Pressing
2. Powder for Additive Manufacturing
3. High density powder for MIM and Press & Sinter
4. High density powder for molding & infiltration
5. High density powder for polymer impregnation

4. 1. Powder for Hot Isostatic Pressing
• Powder for filling into canisters (near-net-shaped) for
subsequent consolidation in a HIP-furnace
• HIP-temperatures in the range of 1200-1300°C are sufficient
to obtain full density in the solid state (no liquid phase!)
• Ductility and toughness already present in the particles’
microstructure (by precedent liquid phase sintering)
• The inventive powder is probably the only way for powder-HIP
manufacturing of tungsten heavy alloys
• Powder-HIP will improve size/geometry-capability as well as
material properties of large tungsten heavy alloy parts

5. 2. Powder for Additive Manufacturing
• Powder is fulfilling key criteria for powder bed AM-processes
• Excellent flowability
• High bulk and tap density (60-70 vol-%)
• Chemical homogeneity (not a mixture of elemental particles)
• Radically improved sintering properties vs. pure tungsten
• Ink-jet printing should be the most straight-forward approach!
• 20-100 µm powder for bonded composite parts by infiltration or impregnation
• -45 µm (325 mesh) powder for parts to be fully densified via sintering
• The powder offer an alternative approach to current pure
tungsten powders for ink-jet 3D-printing tungsten/resin
composite parts (collimators, etc.)
• Improved printing and packing properties may be offered (?)
• Increased part strength and W-atom volumetric density obtainable through
solid state sintering before impregnation