The study of ternary carbides formation during SPS consolidation process in the WC–Co–steel system

Machado, Izabel Fernanda; Girardini, L.; Lonardelli, I.; Molinari, A.

doi:10.1016/j.ijrmhm.2009.05.001

Cited by 44 publications

(18 citation statements)

References 15 publications

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“…The generally negative formation enthalpies indicate exothermic formation; the exception is that of W 2 C-ε calculated by using the GGA-PBE exchange-correlation functional. This means that the η-phases are able to form under C deficient or Co rich conditions, in good agreement with previous experimental findings [6,10,13,19,28]. The cohesive energies of WC and W 2 C-ε are lower than those of the other η-phases, indicating that they are the most stable phases.…”

Section: Resultssupporting

confidence: 91%

“…In particular, hardness measured by indentation methods strongly depends on the testing load and time [16]; thus, the hardness of a sample can vary. Dense WC sintered bodies are also difficult to obtain by general vacuum sintering, and several studies have reported that carbon-deficient phases, such as W 2 C, that are softer than WC are frequently detected in WC sintered bodies [13,16,17,44]. Therefore, the experimental hardnesses are lower than the calculated hardnesses.…”

Section: Accepted Manuscriptmentioning

confidence: 94%

“…However, Co can form W x Co y C (η-phases) during powder preparation and sintering. These phases form when C is deficient in Co-rich regions [13][14][15], and degrade the mechanical properties of the resulting composite [10,16,17].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

First-principles calculations of the phase stability and the elastic and mechanical properties of η-phases in the WC–Co system

Kim

Suh

Kang

2016

Journal of Alloys and Compounds

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Section: Resultssupporting

confidence: 91%

Section: Accepted Manuscriptmentioning

confidence: 94%

See 1 more Smart Citation

First-principles calculations of the phase stability and the elastic and mechanical properties of η-phases in the WC–Co system

Kim

Suh

Kang

2016

Journal of Alloys and Compounds

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“…7 In addition, the benefits of the method include lower sintering temperature and high heating rate. 8 As far as the high-T C superconductors are concerned, the SPS method has been used for synthesize MgB 2 (Ref. 9) by either starting from reacted powders 10 or from reactants precursors.…”

mentioning

confidence: 99%

Consolidation of Bi-2223 superconducting powders by spark plasma sintering

Govea-Alcaide

Machado

Carneiro

et al. 2012

Journal of Applied Physics

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Transport properties near the metal to insulator transition in samarium substituted (Bi,Pb)-2212 systemThe spark plasma sintering (SPS) technique, by using a compacting pressure of 50 MPa, was used to consolidate pre-reacted powders of Bi 1:65 Pb 0:35 Sr 2 Ca 2 Cu 3 O 10þd (Bi-2223). The influence of the consolidation temperature, T D , on the structural and electrical properties has been investigated and compared with those of a reference sample synthesized by the traditional solid-state reaction method and subjected to the same compacting pressure. From the X-ray diffraction patterns, performed in both powder and pellet samples, we have found that the dominant phase is the Bi-2223 in all samples but traces of the Bi 2 Sr 2 CaCu 2 O 8þx (Bi-2212) were identified. Their relative density were $85 % of the theoretical density and the temperature dependence of the electrical resistivity, qðTÞ, indicated that increasing T D results in samples with low oxygen content because the SPS is performed in vacuum. Features of the qðTÞ data, as the occurrence of normal-state semiconductor-like behavior of qðTÞ and the double resistive superconducting transition, are consistent with samples comprised of grains with shell-core morphology in which the shell is oxygen deficient. The SPS samples also exhibited superconducting critical current density at 77 K, J c ð77 KÞ, between 2 and 10 A=cm 2 , values much smaller than $ 22 A=cm 2 measured in the reference sample. Reoxygenation of the SPS samples, post-annealed in air at different temperatures and times, was found to improve their microstructural and transport properties. Besides the suppression of the Bragg peaks belonging to the Bi-2212 phase, the superconducting properties of the post-annealed samples and particularly J c ð77 KÞ were comparable or better than those corresponding to the reference sample. Post-annealed samples at 750 C for 5 min exhibited J c ð77 KÞ $ 130 A=cm 2 even when uniaxially pressed at only 50 MPa. V C 2012 American Institute of Physics. [http://dx.

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“…This tertiary phase is referred to as an eta (η) phase and is generally represented as carbon‐deficient M x W y C, where x + y = 6. Such η‐phases are often regarded as embrittling and undesirable, and their presence can result in degradation of mechanical properties in steels …”

Section: Introductionmentioning

confidence: 99%

Suppressing η‐phase development in steel‐cemented tungsten carbide: A spark plasma sintering study

et al. 2018

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We describe the phase stability of a cemented tungsten carbide prepared using a high-vanadium tool steel as the cementing/binder phase and confirm suppression of (Fe, W) 6 C g-phase formation, attributed to the preferential formation of a V 0.78 W 0.22 C 1Àx phase that exists as islands within the Fe-rich binder matrix. The samples were prepared using spark plasma sintering (SPS), starting from commercially available WC and A11-LVC tool steel powders. The starting powders were ball milled adding 10, 15, and 20 vol.% steel. An A11-LVC tool steel was chosen as a low-cost hard steel (49 HRC) that does not contain Ni or Co but has a high vanadium (~9 wt.%) and carbon (~1.75 wt.%) content. Our results show that sintering by SPS can produce high-density (>98%) WC-steel specimens in which the matrix wets the WC grain surfaces and formation of the brittle g-phase is avoided. The g phase is often regarded as embrittling and undesirable, and its presence can result in degradation of mechanical properties. Microhardness values for the WC-10 and WC-15 vol.% steel samples were 12.3 AE 1.2 and 13.0 AE 0.9 GPa, respectively, whereas the fracture toughness values were 8.83 AE 0.48 and 8.81 AE 0.61 MPaÁm 1/2 , respectively. K E Y W O R D Scarbides, spark plasma sintering, tungsten/tungsten compounds

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The study of ternary carbides formation during SPS consolidation process in the WC–Co–steel system

Cited by 44 publications

References 15 publications

First-principles calculations of the phase stability and the elastic and mechanical properties of η-phases in the WC–Co system

First-principles calculations of the phase stability and the elastic and mechanical properties of η-phases in the WC–Co system

Consolidation of Bi-2223 superconducting powders by spark plasma sintering

Suppressing η‐phase development in steel‐cemented tungsten carbide: A spark plasma sintering study

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