Melting and phase transformation of hardmetal powders

Harmat, P.; Kotsis, I.; Laczkó, László; Bartha, L.

doi:10.1016/s0167-2738(01)00769-x

Cited by 13 publications

(6 citation statements)

References 4 publications

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“…In other words, the decrease of WC particle size can lower the liquid phase formation temperature of WC-Co [19,20]. The differences on the liquid phase formation temperature of CM-1 and CM-2 confirm the effect of WC particle size on the liquid phase formation temperature.…”

Section: Discussionmentioning

confidence: 57%

Influences of the preparation methods of WC–Co powders on the sintering and microstructure of coarse grained WC–8Co hardmetals

Sun

Jiao

et al. 2015

International Journal of Refractory Metals and Hard Materials

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Section: Discussionmentioning

confidence: 57%

Influences of the preparation methods of WC–Co powders on the sintering and microstructure of coarse grained WC–8Co hardmetals

Sun

Jiao

et al. 2015

International Journal of Refractory Metals and Hard Materials

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“…Even though sintering of microstructured WC-Co composites is usually achieved via a liquid-phase sintering process [5], solid-state sintering procedures, which are carried out below the lowest melting point of the system [6][7][8][9], have received much attention since nanocrystalline powders are used as a starting source with the aim of producing bulk nanostructured materials. Furthermore, it is known that submicron WC-Co composites can exhibit superior properties (e.g., hardness or fracture toughness) than conventional (microstructured) cemented carbides [3,[10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…Nanocrystalline powders are commonly prepared by mechanochemical processes [15,16] or mechanical alloying [1,17]. Diverse consolidation techniques, such as hot isostatic pressing [14,18], spark plasma sintering [19], microwave sintering [14], powder injection moulding [20] or extrusion [5], have been reported. To restrain grain growth, sometimes, inhibitors (such as VC or Cr 3 C 2 ) are added in small percentages, either during the milling [11,17,21] or during the chemical carburization routes [15] used to prepare the cemented carbides.…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution during solid-state sintering of ball-milled nanocomposite WC–10 mass% Co powders

et al. 2007

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The microstructural evolution during solid-state sintering of nanocrystalline WC–10 mass% Co powders, prepared by different ball-milling processes to give rise to diverse mechanical activation states, is investigated. During sintering, two ternary carbides, Co6W6C and Co3W3C, form at the binder phase which surrounds WC particle aggregates. The overall microstructure of the sintered material (including the formation of these carbides) is found to be very sensitive to the initial state of the powders, even more than to the sintering temperature and/or sintering time. In addition, the nanocrystalline nature of the composites is preserved during the solid-state sintering, in part assisted by the formation of these complex carbides and decarburization. This nanostructure yields moderate microhardness and fracture toughness values, in spite of the remaining levels of porosity.

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“…Incluso, hay autores que hablan de evidencias de fusión localizada a temperaturas muy por debajo de la eutéctica [25] . Sin embargo, esta rápida cinética de densificación dificulta el control del crecimiento de grano, lo que resulta el principal problema del procesado de estos polvos [23 y 26] .…”

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“…En este punto, los granos de WC se reacomodan y forman un esqueleto sólido, rígido, por lo que la densificación completa sólo puede justificarse por mecanismos de fluencia del cobalto, altamente deformado, o por fenómenos de difusión [1] . Esta eliminación de la porosidad residual, en estado sólido, después de la formación del esqueleto de carburos, es un aspecto a resolver, aunque algunos autores la justifican por la presencia de pequeñas cantidades de fase líquida, a temperaturas muy inferiores a la eutéctica [25] .…”

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Study of the sintering behavior of fine, ultrafine and nanocrystalline WC-Co mixtures obtained by high energy milling

et al. 2008

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E Es st tu ud di io o d de el l c co om mp po or rt ta am mi ie en nt to o d du ur ra an nt te e l la a s si in nt te er ri iz za ac ci ió ón n d de e m me ez zc cl la as s W WC C--C Co o f fi in na as s, , u ul lt tr ra af fi in na as s y y n na an no oc cr ri is st ta al li in na as s o ob bt te en ni id da as s p po or r m mo ol li ie en n--d da a d de e a al lt ta a e en ne er rg gí ía a ( (• •) ) M.D. Salvador*, V. Bonache*, V. Amigó* y D. Busquets* R Re es su um me en n En este trabajo se ha estudiado el comportamiento, durante la sinterización, de mezclas WC-12Co finas, ultrafinas y nanométricas obtenidas por molienda de alta energía y de material nanométrico comercial, a fin de evaluar el efecto del tamaño de partícula y del proceso de obtención del polvo en la densificación, desarrollo microestructural y propiedades mecánicas del producto final. La consolidación de las mezclas se ha realizado mediante compactación uniaxial y sinterización en vacío y por compactación isostática en caliente. Los materiales sinterizados se han evaluado mediante medidas de densidad, dureza y tenacidad a fractura por indentación y se han caracterizado microestructuralmente mediante microscopía óptica y microscopía electrónica de barrido y de transmisión. Los resultados obtenidos ponen de manifiesto las mejoras en comportamiento resistente de los materiales obtenidos a partir polvos nanométricos, a pesar del engrosamiento de grano experimentado durante la sinterización, destacando el material nanométrico de molienda, que presenta valores de dureza superiores a los 1.800 HV. P Pa al la ab br ra as s c cl la av ve eWc-Co; Molienda de alta energía; Polvos nanocristalinos; HIP; Crecimiento de grano.S St tu ud dy y o of f t th h e e s si in nt te er ri in ng g b be eh ha av v i io o r r o o f f f fi in n e e, , u ul lt tr ra af fi in n e e a an nd d n na an no oc c r ry ys s t ta al ll li in ne e W WC C--C Co o m mi ix xt tu ur re es s o ob bt ta ai in ne ed d b by y h hi ig gh h e en ne er rg gy y m mi il ll li in ng g A Ab bs st tr ra ac ct tIn this work the sintering behaviour of fine, ultrafine and nanocrystalline WC-12Co mixtures obtained by high energy milling, as well as commercial nanopowders, have been studied, in order to evaluate the effect of the particle size and the powder processing, in the densification, microstructural development and mechanical properties of the final product. The consolidation of the mixtures has been made by uniaxial pressing and sintering in vacuum, and by hot isostatic pressing. The sintered materials have been evaluated by measures of density, hardness and indentation fracture toughness, and microstructurally characterized by optical microscopy and scanning and transmission electronic microscopy (SEM and TEM). The results show the improvements in resistant behaviour of the materials obtained from nanocrystalline powders, in spite of the grain growth experienced during the sintering. The best results were obtained for the milling nanocrystalline material, which presents values of hardness hig...

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Melting and phase transformation of hardmetal powders

Cited by 13 publications

References 4 publications

Influences of the preparation methods of WC–Co powders on the sintering and microstructure of coarse grained WC–8Co hardmetals

Influences of the preparation methods of WC–Co powders on the sintering and microstructure of coarse grained WC–8Co hardmetals

Microstructural evolution during solid-state sintering of ball-milled nanocomposite WC–10 mass% Co powders

Study of the sintering behavior of fine, ultrafine and nanocrystalline WC-Co mixtures obtained by high energy milling

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