Features of β→α transformation in electroexplosive tungsten nanopowders

X-ray investigations of tungsten nanopowder produced with wire electrical explosion (WEE) have been carried out. It was found that two polymorph phases, α-W and β-W, are simultaneously present in the nanopowder. During annealing in argon, β-phase is first amorphised and then disappears. In contrast to α-phase which does not practically differ from that of standard material, β-W is characterized with microdeformations of the lattice (increased lattice parameter). It is assumed that it is a kind of excess energy storage in nanoparticles of electroexplosive tungsten.