Formation Process of Microstructure in Laser Powder Bed Fusion with WC Cemented Carbide Powder

Ibe, Hiroyuki; Kato, Yuta; Yamada, Jyunya; Kato, Masaki; Suzuki, Asuka; Takata, Naoki; Kobashi, Makoto

doi:10.2497/jjspm.67.313

Cited by 5 publications

(3 citation statements)

References 20 publications

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“…The cross-sectional SEM images of the printed samples from different powders are also exhibited in Figure 2. According to the reported works, 24 the bright phase should be W 2 C, whereas the dark-gray phase is ƞ, see Figure 2H. Compared with the raw WC-Co powder, the introduction of C nanoparticles and CNTs significantly decreases the amount of ƞ phase (Co 4 W 2 C), see Figure 2B,D,F.…”

Section: Deposition Behavior and Optimization Of Carbon Sourcementioning

confidence: 99%

“…22,23 As a result, this not only exacerbates the C-loss to form more ƞ phases but also induces the numerous graphite phases. 17,24 Both ultimately deteriorate the mechanical properties of the cemented carbide. Apparently, mixing the excessive C additive approach used in the sintering technology is not applicable to the carbon compensation during LPBF because of distinct thermal conditions.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, the undissolved carbon black immediately transforms into graphite phase with the high temperature during LPBF 22,23 . As a result, this not only exacerbates the C‐loss to form more ƞ phases but also induces the numerous graphite phases 17,24 . Both ultimately deteriorate the mechanical properties of the cemented carbide.…”

Section: Introductionmentioning

confidence: 99%

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Elimination of ƞ phase in WC–Co cemented carbides during laser powder bed fusion by powder coating compensation strategy

et al. 2022

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The formation of ƞ phase induced by the C-loss for the laser powder bed fusion (LPBF) of WC-Co cemented carbides largely deteriorates the fracture toughness. The current approach of mixing C additive into powder cannot mitigate the ƞ phase formation. This study proposed a new carbon compensation strategy of coating carbon resource on powder surface by fluidized bed chemical vapor deposition to address this issue. C nanoparticles and carbon nanotubes (CNTs) were selectively deposited on WC-Co powder to make uniform C-and CNTs-coated powders by tuning the deposition temperature. Compared with CNTs-coated powder and C-WC-Co powder mixtures, the C-coated powder was more effective in impeding the ƞ phase formation because it had higher reactivity and stronger dissolution ability to compensate the C-loss in the Co-W-C liquid. However, the single-carbon compensation was not enough to eliminate the ƞ phase due to the extreme nonequilibrium characteristics of LPBF, which required secondary heat treatment. The conventional heat treatment procedure of 1000 • C for 3 h eliminated the ƞ phase for the C-coated powder but failed for the C-WC-12Co powder mixtures. Because of the absence of ƞ phase, the heattreated sample made from C-coated powder exhibited the highest transverse rupture strength.

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Section: Deposition Behavior and Optimization Of Carbon Sourcementioning

confidence: 99%