New insights into the accelerated sintering of tungsten with trace nickel addition

Abstract

In Ni-doped W alloys, 1–4 wt% of Ni was often employed to accelerate densification in conventional sintering process but at the expense of restricted service temperatures because of formation of liquid phase. To break the dilemma, in this work 0.1 wt% Ni was alloyed into W matrix and achieved 98% relative density. The densification and grain growth behaviors of both pure and nickel doped tungsten compacts were investigated, in which a potential new accelerated sintering mechanism by solid-solution alloying was explored. First-principles calculations demonstrated the transition barrier for vacancies in W system was lowered by 34% upon Ni doping. This alloying process therefore was beneficial for lattice diffusion of tungsten that, in turn, improved the sintering performance and service abilities of tungsten-nickel alloy.