Phase diagram of the Co-VC-NbC system

Dmitrieva, G. P.; Krasnokutskaya, Z. B.; Belyavina, N. N.; Shurin, A. K.

doi:10.1007/bf00794804

Cited by 8 publications

(5 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Several phase diagrams of WC-Co [1,2] show that the lowest melting eutectic composition occurs at 1250-1275 • C, and cobalt was found to exist in a solid solution with up to 20 wt.% W, but no reports exist about a solid solution of WC with Co. According to Storms Edmond [3], vacancies can be introduced in WC on the carbon site resulting in WC x, where x < 1, in which case the "a" parameter of the WC unit cell does not change, but the "c" parameter decreases with decreasing carbon content.…”

Section: Conventional Sintering Mechanismsmentioning

confidence: 99%

“…Therefore, the cooling rate, when the cobalt is still liquid, has no real importance for the tungsten distribution in the binder phase. The last liquid cobalt (∼1275 • C) will have a nearly homogeneous concentration of ∼6 at.% tungsten (∼18 w% W) and ∼12 at.% carbon (∼2.4 w% C), according to the phase diagram [1,2].…”

Section: Diffusion Of Tungsten and Carbon Into Cobaltmentioning

confidence: 99%

See 1 more Smart Citation

Comparison between microwave and conventional sintering of WC/Co composites

Breval

Cheng

Agrawal

et al. 2005

Materials Science and Engineering: A

212

View full text Add to dashboard Cite

Section: Conventional Sintering Mechanismsmentioning

confidence: 99%

Section: Diffusion Of Tungsten and Carbon Into Cobaltmentioning

confidence: 99%

Comparison between microwave and conventional sintering of WC/Co composites

Breval

Cheng

Agrawal

et al. 2005

Materials Science and Engineering: A

212

View full text Add to dashboard Cite

“…However it is reasonable to consider that the structure has a type of (W,V) 2 C because the solubility of W into (W,V)C is limited at 25 at.% to form a fixed structure; whereas (W, V) 2 C is a completely solubility type. The formation of (W, V) 2 C may be closely related to the over-concentration of V. The solubility of V into the Co-phase is about 4.7 at.% at an equilibrium state [24]. If the concentration of V caused by the migration of WC grains is over at the concentration of the solubility limit, it is reasonable to form the compound such as (W, V) 2 C. In addition, the lattice mismatching between WC and (W, V) 2 C is very small as recognized in the HRTEM image, as shown in Fig.…”

Section: The Morphology Change Of Wc Grains In Vc-doped Wc-comentioning

confidence: 99%

High resolution transmission electron microscopy study in VC-doped WC–Co compound

Yamamoto

Ikuhara

Sakuma

2000

Science and Technology of Advanced Materials

View full text Add to dashboard Cite

Microstructure evolution in VC-doped WC-Co was investigated using high-resolution transmission electron microscopy (HRTEM) associated with X-ray energy dispersive spectroscopy (EDS) with a special interest in WC/Co and WC/WC boundaries. It was found that the morphology of carbide grains changed largely by the addition of VC. The WC/Co interfaces tend to form facetting with fine multi-steps of (0001) and {10 10}habits by VC-doping. In addition, the facetting morphology of WC/Co interfaces was confirmed to be already formed in solid state from an examination with a quenched compound from 1200ЊC, which is below the eutectic temperature of 1320ЊC between WC and Co system. EDS analysis with the sub-nano scale probe revealed that the doped V was strongly concentrated to the two habits. However, the amount of concentrated V was different among them, i.e. more at (0001) habit than at {10 10} habits. V is considered to be concentrate at the boundary during grain growth to accompany the migration of the two habits because most of the doped V solves into the Co-phase and not into WC grains. Thus it can be supposed that the retardation of the grain growth of WC grains is due to the concentration of V at the migration front of the two habits.Meanwhile, WC/WC boundaries were found to be directly in contact each other and free from the second phase such as the amorphous phase whereas the segregation of Co and also V could be detected by EDS analysis. This fact suggests that the grain boundary migration between the adjacent WC grains may be mainly controlled by the solid-solid diffusion. ᭧

show abstract

“…If we consider the solubility of V in the Co-W-V-C phase (i.e., the liquid and solid Co phases) of a WC-VC-Co cemented carbide based on a pseudo-binary VC-Co phase diagram, 9) then it is apparent that the amount of V added in a previous work 7) was less than the solubility limit of V in the liquid Co phase, but greater than that in the solid Co phase. Given this difference in solubility limits, it is only natural to assume that (V,W)C x segregates on the WC surface during cooling.…”

Section: Introductionmentioning

confidence: 99%

Segregation of Dopants at WC/Co and WC/WC Interfaces in Solid-State-Sintered WC-VC-Cr<sub>3</sub>C<sub>2</sub>-Co Cemented Carbides

Kawakami

Kitamura

2015

Mater. Trans.

View full text Add to dashboard Cite

The segregation of V and Cr at WC/Co and WC/WC interfaces in ultrafine-grained WC-0.7VC-1.4Cr 3 C 2 -10Co (mass%) cemented carbides produced through solid-state sintering and semi-sintering was investigated. This segregation was compared against that of a liquid-statesintered specimen to elucidate the mechanism by which WC grain growth is inhibited by V and Cr. The V and Cr were found to segregate at the WC/Co and WC/WC interfaces during solid-state sintering and semi-sintering, but no differences were observed in the V and Cr concentrations at the interfaces among the liquid-state-sintered, solid-state-sintered and semi-sintered specimens. Furthermore, these concentrations were unchanged by quenching of the solid-state-sintered specimen. From these results, it was concluded that (V,W,Cr)C x segregation layers are stably formed at the WC/Co and WC/WC interfaces at a temperature below the solidus of the Co phase, but almost dissolve in the liquid Co phase once the temperature exceeds its liquidus. Thus, the (V,W,Cr)C x segregation layers observed at the WC/Co and WC/WC interfaces at room temperature are formed during the cooling that follows the liquid-state sintering. This supports the finding that WC grain growth is inhibited by the adsorption of dopant atoms onto steps/kinks on the WC surface during liquid-state sintering, as well as by the segregation layers formed on the WC surface during solid-state sintering.

show abstract

Phase diagram of the Co-VC-NbC system

Cited by 8 publications

References 4 publications

Comparison between microwave and conventional sintering of WC/Co composites

Comparison between microwave and conventional sintering of WC/Co composites

High resolution transmission electron microscopy study in VC-doped WC–Co compound

Segregation of Dopants at WC/Co and WC/WC Interfaces in Solid-State-Sintered WC-VC-Cr<sub>3</sub>C<sub>2</sub>-Co Cemented Carbides

Contact Info

Product

Resources

About