Effect of the Mechanical Activation Time on the Density of Fine-Grained 90W-7Ni-3Fe Alloy Synthesized by Spark Plasma Sintering

The effect of the high-energy mechanical activation (HMA) time on the microstructure of heavy tungsten 90% W-7% Ni-3% Fe alloy (VNZh-90) and its solid-phase sintering kinetics was studied. Alloy specimens were manufactured by vacuum spark plasma sintering (SPS). It has been shown that the density of alloy VNZh-90 depends on the HMA time nonmonotonically with a minimum. It has been demonstrated that the kinetics of the SPS of mechanically activated nanopowders has a two-stage character; the sintering rate depends on the Coble creep rate and the diffusion rate of W atoms in the crystal lattice of the nickel based gamma-phase.