The influence of the local effect of electric current on densification of tungsten powder during spark plasma sintering

Abstract The local overheating effect induced by the uneven distribution of current density is a crucial physical phenomenon during the spark plasma sintering (SPS) of metallic powder, which can promote the densification. In order to investigate the local effects of current on densification kinetics behaviors of tungsten powder during SPS, an electromigration-creep model was constructed by introducing the local current density and was used to describe the densification process. The numerical calculation based on the model indicates that the local effect of electric current can induce a certain impact on densification during SPS at the intermediate sintering stage, in which an extremely high local current density is generated. Additionally, with the decrease of porosity, the local effect of electric current on densification is weakened.