Effect of nanocrystalline tungsten powders on the microstructure and properties of liquid-phase sintered 93 W alloys

Ultra-fine tungsten powders was produced by high energy mechanically milling in a high-energy attritor mill. Then the mixing powders were consolidated into green compacts by CIP and liquid-phase sintered at 1465°C in the dissociated ammonia atmosphere. Effect on the microstructure and the properties of liquid-phase sintered 93W-4.9Ni-2.1Fe tungsten heavy alloys composed of nanocrystalline sub-micron tungsten powders was investigated. Liquid-phase sintered tungsten heavy alloys exhibited high relative density (above 99.7%), and fine spherical tungsten particles embedded homogeneously in the matrix were obtained due to the combination of ultra-fine tungsten powders and lower sintering temperature. Mechanical properties have been improved compared with the traditionally sintering alloys. The mechanical properties of a tungsten heavy alloy were found mainly dependent on the particles size of raw tungsten powders and liquid-phase sintering temperature.