Carbide grain growth in cemented carbides

Mannesson, Karin; Jeppsson, Johan; Borgenstam, Annika; Ågren, John

doi:10.1016/j.actamat.2010.11.056

Cited by 77 publications

(25 citation statements)

References 13 publications

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“…The grain growth of WC-9Co/1 in general is slightly higher compared to WC-6Co/1 consolidated from the same starting powder but with lower Co content. Co content contributed to the recrystallization and grain growth of near nano-and nanostructured cemented carbides sintered in hydrogen, confirming the role of Co in grain growth, already researched by various scientists [11,[13][14][15]. The smallest grain sizes were measured for WC-6Co/2, 95 nm and the addition of Cr 3 C 2 and VC, but in higher content compared to other mixtures.…”

Section: Density and Microstructural Characteristicssupporting

confidence: 52%

“…Still, scientists have found that Ostwald ripening/coarsening is not sufficient to explain grain growth in nanostructured cemented carbides with lower Co content where WC grains are not surrounded by Co binder but with one another. A new mechanism suggested by numerous scientists [6,11,12] is coalescence. Coalescence is the process by which two or more faceted WC grains merge during contact and consequently form a larger grain by diffusion and grain rotation thought rapid mass transport [11].…”

Section: Density and Microstructural Characteristicsmentioning

confidence: 99%

“…A new mechanism suggested by numerous scientists [6,11,12] is coalescence. Coalescence is the process by which two or more faceted WC grains merge during contact and consequently form a larger grain by diffusion and grain rotation thought rapid mass transport [11]. This mechanism can take place only if the grains are already bonded to each other, with a grain boundary and preferred orientations, as presented in Figure 5.…”

Section: Density and Microstructural Characteristicsmentioning

confidence: 99%

“…Both growth processes must be avoided in order to obtain satisfactory properties in the sintered products since mechanical properties of ultrafine and nanostructured cemented carbides are directly dependent on the developed microstructure: WC grain size, mean free path of Co and contiguity of WC grains [2,10]. Homogeneous microstructure without grain growth and homogeneous distribution of cobalt between carbide grains lead to optimal strength and improvements of hardness and toughness, while microstructural irregularities, like porosity and especially abnormal grain growth, result in poor transverse rupture strength [11]. Abnormal grain growth is characteristic of a system with faceted grains, which possess a singular interface and anisotropic surface energy.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Influence of Grain Growth Inhibitors and Powder Size on the Properties of Ultrafine and Nanostructured Cemented Carbides Sintered in Hydrogen

Fabijanić

Jakovljević

Franz

et al. 2016

Metals

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Abstract:The influence of grain growth inhibitors and powder size on the microstructure and mechanical properties of ultrafine and nanostructured cemented carbides was researched. Three different WC powders, with an addition of different type and content of grain growth inhibitors GGIs, VC and Cr 3 C 2 and with d BET grain sizes in the range from 95 to 150 nm were selected as starting powders. Four different mixtures with 6 and 9 wt. % Co were prepared. The consolidated samples are characterized by different microstructural and mechanical properties with respect to the characteristics of starting powders. Increased sintering temperatures led to microstructural irregularities in the form of a discontinuous WC growth, carbide agglomerates and abnormal grain growth as a consequence of coalescence via grain boundary elimination. The addition of 0.45% Cr 3 C 2 contributed to microstructure homogeneity, reduced discontinuous and continuous grain growth, and increased Vickers hardness by approximately 70 HV and fracture toughness by approximately 0.15 MN/m 3/2 . The reduction of the starting powder to a real nanosize of 95 nm resulted in lower densities, and significant hardness increase, with a simultaneously small increase in fracture toughness. The consolidation of real nanopowders (d BET < 100 nm) solely by conventional sintering in hydrogen without isostatic pressing is not preferred.

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Section: Density and Microstructural Characteristicssupporting

confidence: 52%

Section: Density and Microstructural Characteristicsmentioning

confidence: 99%

Section: Density and Microstructural Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of Grain Growth Inhibitors and Powder Size on the Properties of Ultrafine and Nanostructured Cemented Carbides Sintered in Hydrogen

Fabijanić

Jakovljević

Franz

et al. 2016

Metals

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“…In cemented carbides, where normal WC grain size is of the order of µm or less, abnormal grain growth can sometimes lead to grain sizes of several hundred µm. In the case of cemented carbides the diffusion distances are very short and the common faceted shape of the WC particles indicates that the difficulty in forming new atomic layers rather than long-range diffusion is the rate controlling mechanism 13 .…”

Section: Introductionmentioning

confidence: 99%

Study HTHP Sintered WC/Co Hardmetal

et al. 2016

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WC/Co is widely used as cutting tools, because has a unique combination of high strength, hardness, toughness, and moderate stiffness, especially with fine grained WC and finely distributed cobalt. WC/ Co powder mixture sinters by different methods such as vacuum sintering, microwave sintering and SPS. High pressure high temperature (HPHT) sintering is a proposed method that can result in better distribution of cobalt and avoid undesirable phases by using high pressure, high temperature and very short sintering time. In this study, a powder mixture of WC-10 wt% Co was sintered by HPHT at 1500 to 1900ºC under a pressure of 7.7 GPa for 2 minutes. Microstructural/structural analyses were performed by SEM/EDS. Hardness and compression test were also done to obtain the effect of sintering parameters. It was found that HPHT sintering method can be used to produce WC/Co hardmetal with low sintering time and high production rate. It was realized that increasing sintering temperature in HTHP sintering method results in increasing density but hardness and compression strength increase by increasing sintering temperature up to 1800 ºC and then decrease.

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Tungsten Carbides

Shabalin

2022

Ultra-High Temperature Materials IV

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Carbide grain growth in cemented carbides

Cited by 77 publications

References 13 publications

Influence of Grain Growth Inhibitors and Powder Size on the Properties of Ultrafine and Nanostructured Cemented Carbides Sintered in Hydrogen

Influence of Grain Growth Inhibitors and Powder Size on the Properties of Ultrafine and Nanostructured Cemented Carbides Sintered in Hydrogen

Study HTHP Sintered WC/Co Hardmetal

Tungsten Carbides

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