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

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 behavior...

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Bibliographic Details
Published in:Powder technology 2019-11, Vol.356, p.769-777
Main Authors: Deng, Shenghua, Zhao, Hongjin, Li, Ruidi, Yuan, Tiechui, Li, Lanbo, Cao, Peng
Format: Article
Language:English
Subjects:
Creep (materials)
Current density
Current distribution
Densification
Electric current
Electric currents
Electromigration
Local current
Local current density
Local effect
Metal powders
Overheating
Plasma sintering
Porosity
Spark plasma sintering
Tungsten
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Summary: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. [Display omitted] •A densification kinetics model considering the local effect of current was constructed.•The local effect of current on densification was studied quantitatively by the kinetics model.•The model is consistent with experiments.•The local effect of current on densification was found weakening with the decrease of porosity.
ISSN:0032-5910
1873-328X
DOI:10.1016/j.powtec.2019.08.108