Hot pressing of tungsten and its pseudoalloys. II

Karpinos, D. M.; Kravchenko, A. A.; Pilipovskii, Yu. L.; Ткаченко, В. Г.; Shamatov, Yu. M.

doi:10.1007/bf00793852

Cited by 4 publications

(4 citation statements)

References 3 publications

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“…4), Q was found to be 433.76 kJ/mol. [3,18] and with the activation energy value of the grain boundary diffusion (385 kJ/mol) determined by the tracer diffusion method in the temperature range of 1400 °C to 2200 °C [38]. This finding supports the view of the grain boundary diffusion as the rate limiting mechanism.…”

Section: W Powder Densification Kineticssupporting

confidence: 71%

“…This may indicate that SPS of W powder is affected by the contribution of two or more mass transfer mechanisms. Kapinos et al speculated that dislocation climb controlled by diffusion (m = 0.2 to 0.25) was the consolidation mechanism for HP of W during the final stage of sintering [3,18]. Therefore, one…”

Section: W Powder Densification Kineticsmentioning

confidence: 99%

“…Pressure-assisted sintering methods were also utilized for the consolidation of W powders. Karpinos et al reported that W powder could be sintered to 94 % under 2300 °C and 24.52 MPa using hot pressing (HP) [3]. Hot isostatic pressing (HIP) using 14 µm W powder achieved 92.7 % with the processing conditions of 1277 °C and 195 MPa [4].…”

Section: Introductionmentioning

confidence: 99%

“…There are few reports on the determination of the sintering mechanisms of W by pressure assisted methods (HP and SPS). Karpinos et al [3,18] investigated W densification using HP and used a sintering kinetics model, which had been earlier employed by Kothari [14]. Densification mechanisms were subdivided into three regions with respect to the relative density.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Densification mechanism and mechanical properties of tungsten powder consolidated by spark plasma sintering

Lee

McKittrick

Ivanov

et al. 2016

International Journal of Refractory Metals and Hard Materials

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The dominant densification mechanism of a tungsten powder processed by spark plasma sintering (SPS) is revealed by the continuum theory of sintering-based regression of the experimental data on the powder consolidation carried out at the temperatures from 1600 °C to 1800 °C and pressure levels of 60 MPa and 120 MPa. The strain rate sensitivity is determined to be 0.39 and the sintering activation energy is 412 kJ/mol. It appears that the main mechanism of tungsten powder densification compaction is grain boundary sliding controlled by dislocation climb with the dislocations moving along grain boundaries. The evidence of the superplastic-like behavior of the tungsten powder during SPS is also supported by electron backscatter diffraction microstructure analysis of the compacted specimens. The relative density of the compacted pellets reaches 81~95%, depending on the SPS temperature conditions. The experimental outcomes indicate that the carbon uptake during SPS results in the formation of tungsten carbide at the surface of compacted specimens. Based on the experimental data, the diffusion coefficient of carbon in tungsten is obtained and is found to be similar to literature values.

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Section: W Powder Densification Kineticssupporting

confidence: 71%

Section: W Powder Densification Kineticsmentioning

confidence: 99%