A Study of the Impact of Graphite on the Kinetics of SPS in Nano- and Submicron WC-10%Co Powder Compositions

This study investigates the impact of carbon on the kinetics of the spark plasma sintering (SPS) of nano- and submicron powders WC-10wt.%Co. Carbon, in the form of graphite, was introduced into powders by mixing. The activation energy of solid-phase sintering was determined for the conditions of isothermal and continuous heating. It has been demonstrated that increasing the carbon content leads to a decrease in the fraction of η-phase particles and a shift of the shrinkage curve towards lower heating temperatures. It has been established that increasing the graphite content in nano- and submicron powders has no significant effect on the SPS activation energy for “mid-range” heating temperatures, QS(I). The value of QS(I) is close to the activation energy of grain-boundary diffusion in cobalt. It has been demonstrated that increasing the content of graphite leads to a significant decrease in the SPS activation energy, QS(II), for “higher-range” heating temperatures due to lower concentration of tungsten atoms in cobalt-based γ-phase. It has been established that the sintering kinetics of fine-grained WC-Co hard alloys is limited by the intensity of diffusion creep of cobalt (Coble creep).

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Effect of Spark Plasma Sintering on the Microstructure Evolution and Properties of M3:2 High-Speed Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.788.329 ◽

2014 ◽

Vol 788 ◽

pp. 329-333

Author(s):

Rui Zhou ◽

Xiao Gang Diao ◽

Jun Chen ◽

Xiao Nan Du ◽

Guo Ding Yuan ◽

...

Keyword(s):

Powder Metallurgy ◽

Spark Plasma Sintering ◽

High Speed ◽

Bending Strength ◽

Sintering Temperature ◽

High Speed Steel ◽

Continuous Heating ◽

Plasma Sintering ◽

Spark Plasma ◽

The Impact

Effects of sintering temperatures on the microstructure and mechanical performance of SPS M3:2 high speed steel prepared by spark plasma sintering was studied. High speed steel sintering curve of continuous heating from ambient temperature to 1200°C was estimated to analyze the sintering processes and sintering temperature range. The sintering temperature within this range was divided into groups to investigate hardness, relative density and microstructure of M3:2 high-speed steel. Strip and quadrate carbides were observed inside the equiaxed grains. SPS sintering temperature at 900°C can lead to nearly full densification with grain size smaller than 20μm. The hardness and bending strength are higher than that of the conventionally powder metallurgy fabricated ones sintered at 1270°C. However, fracture toughness of the high speed steel is lower than that of the conventional powder metallurgy steels. This can be attributed to the shape and distribution of M6C carbides which reduce the impact toughness of high speed steels.

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Study of the kinetics of spark plasma sintering of ultrafine-grained hard alloys WC-10%Co

Journal of Physics Conference Series ◽

10.1088/1742-6596/1431/1/012030 ◽

2020 ◽

Vol 1431 ◽

pp. 012030

Author(s):

E A Lantsev ◽

V N Chuvil’deev ◽

A V Nokhrin ◽

M S Boldin ◽

N V Malekhonova ◽

...

Keyword(s):

Spark Plasma Sintering ◽

Hard Alloys ◽

Plasma Sintering ◽

Ultrafine Grained ◽

Spark Plasma ◽

Kinetics Of

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Spark plasma sintering of WC – 10 Co nanopowders with various carbon content obtained by plasma-chemical method

Perspektivnye Materialy ◽

10.30791/1028-978x-2020-8-73-86 ◽

2020 ◽

pp. 73-86

Author(s):

Yu. V. Blagoveshchenskiy ◽

◽

N. V. Isaeva ◽

E. A. Lantsev ◽

M. S. Boldin ◽

...

Keyword(s):

Activation Energy ◽

Carbon Content ◽

Spark Plasma Sintering ◽

High Speed ◽

Diffusion Creep ◽

Powder Materials ◽

Plasma Chemical ◽

Colloidal Graphite ◽

Plasma Sintering ◽

Spark Plasma

The features of high-speed sintering of WC – Co nanopowders with various contents of excess carbon (colloidal graphite) were studied. To obtain powders, a process was used that included plasma-chemical and low-temperature syntheses and a chemical-metallurgical method of applying ultrathin cobalt layers by precipitation from a solution of salts. The consolidation of powder materials was carried out by the method of high-speed Spark Plasma Sintering. It was found that an increase in the concentration of free carbon (colloidal graphite) has the greatest effect on the shrinkage and sintering rate at the stage of intense shrinkage of WC-Co nanopowders. It is shown that an increase in the carbon content in the composition of nanopowders leads to a decrease in the value of sintering activation energy at the stage of intense shrinkage.It has been established that the process of nanopowder compaction at the intense shrinkage stage is determined by the intensity of the plastic flow and the grain boundary diffusion of cobalt. It is shown that the mechanism of plastic deformation of the γ-phase based on cobalt corresponds to the Coble diffusion creep. It was found that an increase in carbon content leads to decreased in activation energy at the intense shrinkage and does not significantly affect at stage III of sintering where decrease in the shrinkage intensity is observed. It was shown that a decrease in the sintering activation energy is due to a decrease in the tungsten concentration in the γ-phase.

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Spark plasma sintering of fine-grained WC hard alloys with ultra-low cobalt content

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2020.157535 ◽

2020 ◽

pp. 157535

Author(s):

E.A. Lantsev ◽

N.V. Malekhonova ◽

A.V. Nokhrin ◽

V.N. Chuvil’deev ◽

M.S. Boldin ◽

...

Keyword(s):

Spark Plasma Sintering ◽

Cobalt Content ◽

Hard Alloys ◽

Fine Grained ◽

Plasma Sintering ◽

Spark Plasma

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Preparation of Fine-Grained CeO2–SiC Ceramics for Inert Fuel Matrices by Spark Plasma Sintering

Inorganic Materials ◽

10.1134/s0020168520120018 ◽

2020 ◽

Vol 56 (12) ◽

pp. 1307-1313

Author(s):

L. S. Alekseeva ◽

A. V. Nokhrin ◽

M. S. Boldin ◽

E. A. Lantsev ◽

A. I. Orlova ◽

...

Keyword(s):

Spark Plasma Sintering ◽

Fine Grained ◽

Sic Ceramics ◽

Plasma Sintering ◽

Spark Plasma

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Ultra-Fine Grained Ti-15Mo Alloy Prepared by Powder Metallurgy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.1276 ◽

2018 ◽

Vol 941 ◽

pp. 1276-1281

Author(s):

Anna Terynková ◽

Jiří Kozlík ◽

Kristína Bartha ◽

Tomáš Chráska ◽

Josef Stráský

Keyword(s):

Powder Metallurgy ◽

Bulk Material ◽

Alpha Phase ◽

Full Density ◽

Fine Grained ◽

Cryogenic Milling ◽

Aircraft Manufacturing ◽

Plasma Sintering ◽

Beta Matrix ◽

Spark Plasma

Ti-15Mo alloy belongs to metastable β-Ti alloys that are currently used in aircraft manufacturing and Ti15Mo alloy is a perspective candidate for the use in medicine thanks to its biotolerant composition. In this study, Ti15Mo alloy was prepared by advanced techniques of powder metallurgy. The powder of gas atomized Ti-15Mo alloy was subjected to cryogenic milling to achieve ultra-fine grained microstructure within the powder particles. Powder was subsequently compacted using spark plasma sintering (SPS). The effect of cryogenic milling on the microstructure and phase composition of final bulk material after SPS was studied by scanning electron microscopy. Sintering at 750°C was not sufficient for achieving full density in gas atomized powder, while milled material could be successfully sintered at this temperature. Alpha phase particles precipitated during sintering and their size, as well as the size of beta matrix grains, was strongly affected by the sintering temperature.

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Ultralow-cobalt hard alloys obtained by spark plasma sintering

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1014/1/012020 ◽

2021 ◽

Vol 1014 (1) ◽

pp. 012020

Author(s):

E A Lantsev ◽

V N Chuvil’deev ◽

A V Nokhrin ◽

M S Boldin ◽

N V Malekhonova ◽

...

Keyword(s):

Spark Plasma Sintering ◽

Hard Alloys ◽

Plasma Sintering ◽

Spark Plasma

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Oxidation behavior of non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution powders in air

Journal of Advanced Ceramics ◽

10.1007/s40145-021-0469-y ◽

2021 ◽

Author(s):

Huilin Lun ◽

Yi Zeng ◽

Xiang Xiong ◽

Ziming Ye ◽

Zhongwei Zhang ◽

...

Keyword(s):

Solid Solution ◽

Oxidation Resistance ◽

Oxidation Behavior ◽

Group Iv ◽

Hypersonic Vehicles ◽

Metal Carbides ◽

Initial Oxidation ◽

Plasma Sintering ◽

Spark Plasma ◽

Kinetics Of

AbstractMulti-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles. However, for group IV transition-metal carbides, the oxidation behavior of multi-component non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution has not been clarified yet. The present work fabricated four kinds of (Zr,Hf,Ti)Cx carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of (Zr,Hf,Ti)Cx in air. The effects of metallic atom composition on oxidation resistance were examined. The results indicate that the oxidation kinetics of (Zr,Hf,Ti)Cx are composition dependent. A high Hf content in (Zr,Hf,Ti)Cx was beneficial to form an amorphous Zr-Hf-Ti-C-O oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance. Meanwhile, an equiatomic ratio of metallic atoms reduced the growth rate of (Zr,Hf,Ti)O2 oxide, increasing its phase stability at high temperatures, which improved the oxidation activation energy of (Zr, Hf, Ti)Cx.

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Comparison of Conventional and Flash Spark Plasma Sintering of Cu–Cr Pseudo-Alloys: Kinetics, Structure, Properties

Metals ◽

10.3390/met11010141 ◽

2021 ◽

Vol 11 (1) ◽

pp. 141

Author(s):

Kirill V. Kuskov ◽

Mohammad Abedi ◽

Dmitry O. Moskovskikh ◽

Illia Serhiienko ◽

Alexander S. Mukasyan

Keyword(s):

Heating Rate ◽

Spark Plasma Sintering ◽

Electric Circuits ◽

Nanostructured Particles ◽

Plasma Sintering ◽

Spark Plasma ◽

The Media ◽

Copper Chromium ◽

Kinetics Of ◽

Structure Properties

Spark plasma sintering (SPS) is widely used for the consolidation of different materials. Copper-based pseudo alloys have found a variety of applications including as electrodes in vacuum interrupters of high-voltage electric circuits. How does the kinetics of SPS consolidation for such alloys depend on the heating rate? Do SPS kinetics depend on the microstructure of the media to be sintered? These questions were addressed by the investigation of SPS kinetics in the heating rate range of 0.1 to 50 K/s. The latter conditions were achieved through flash spark plasma sintering (FSPS). We also compared the sintering kinetics for the conventional copper–chromium mixture and for the mechanically induced copper/chromium nanostructured particles. It was shown that, under FSPS conditions, the observed maximum consolidation rates were 20–30 times higher than that for conventional SPS with a heating rate of 100 K/min. Under the investigated conditions, the sintering rate for mechanically induced composite Cu/Cr particles was 2–4 times higher compared to the conventional Cu + Cr mixtures. The apparent sintering activation energy for the Cu/Cr powder was twice less than that for Cu–Cr mixture. It was concluded that the FSPS of nanostructured powders is an efficient approach for the fabrication of pseudo-alloys.

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