Studies into the impact of mechanical activation on optimal sintering temperature of UFG heavy tungsten alloys

Abstract

The paper dwells on the research conducted into sintering mechanisms, the structure and mechanical properties of ultrafine-grained heavy tungsten W-Ni-Fe alloys. The dependence of alloy density on temperature of sintering (Tsint) is found to be nonmonotonic with a maximum equivalent to the optimal sintering temperature. Studies also encompassed the impact that the size of tungsten particles may have on the optimal Tsint. An increase in time of mechanical activation (MA) and acceleration of grinding bodies accompanied by a decrease in alloy particle size and formation of non-equilibrium solid solutions is shown to reduce the optimal Tsint of alloys. High-energy MA and Spark Plasma Sintering methods were applied to obtain samples of tungsten alloys with high mechanical properties: macroelasticity limit of up to 2,250 MPa, yield strength of up to 2,500 MPa.