Feasibility of Cobalt-Free Nanostructured WC Cutting Inserts for Machining of a TiC/Fe Composite

Gevorkyan, Edwin; Rucki, Mirosław; Sałaciński, Tadeusz; Siemiątkowski, Zbigniew; Nerubatskyi, Volodymyr; Kucharczyk, Wojciech; Chrzanowski, J.; Gutsalenko, Yuriy; Nejman, Mirosław

doi:10.3390/ma14123432

Cited by 21 publications

(10 citation statements)

References 31 publications

(33 reference statements)

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“…To assess the crack resistance of the obtained samples, fracture toughness was calculated from the following equation [ 24 ]:

under the condition of ratio:

where E —an elastic modulus [GPa], Ф —constant [-] that took here the value Ф ≈ 3, l —a crack length measured from the indentation corner [μm], a —half of the length of the indentation diagonal [μm].…”

Section: Methodsmentioning

confidence: 99%

Peculiarities of the Phase Formation during Electroconsolidation of Al2O3–SiO2–ZrO2 Powders Mixtures

et al. 2022

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This paper is devoted to the sintering process of Al2O3–SiO2–ZrO2 ceramics. The studied method was electroconsolidation with directly applied electric current. This method provides substantial improvements to the mechanical properties of the sintered samples compared to the traditional sintering in the air. The research covered elemental and phase analysis of the samples, which revealed phase transition of high-alumina solid solutions into mullite and corundum. Zirconia was represented mainly by tetragonal phase, but monoclinic phase was present, too. Electroconsolidation enabled samples to reach a density of 3.0 g/cm3 at 1300 °С, while the sample prepared by traditional sintering method obtained it only at 1700 °С. For the composite Al2O3—20 wt.% SiO2—10 wt.% ZrO2 fabricated by electroconsolidation, it was demonstrated that fracture toughness was higher by 20–30%, and hardness was higher by 15–20% compared to that of samples sintered traditionally. Similarly, the samples fabricated by electroconsolidation exhibited elastic modulus E higher by 15–20%. The hypothesis was proposed that the difference in mechanical and physical properties could be attributed to the peculiarities of phase formation processes during electroconsolidation.

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“…To assess the crack resistance of the obtained samples, fracture toughness was calculated from the following equation [ 24 ]:

under the condition of ratio:

Section: Methodsmentioning

confidence: 99%

Peculiarities of the Phase Formation during Electroconsolidation of Al2O3–SiO2–ZrO2 Powders Mixtures

et al. 2022

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“…Hardness was measured with diamond pyramid indentation using a NEXUS 4504 microhardness tester (Innovatest, Maastricht, The Netherlands). From these measurements, both hardness and fracture toughness were calculated using the standard procedure [22]. The mass content of the components was determined according to the standard recommendations concerning alumina [23].…”

Section: Methodsmentioning

confidence: 99%

Analysis of the Electroconsolidation Process of Fine-Dispersed Structures Out of Hot Pressed Al2O3–WC Nanopowders

et al. 2021

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Fabrication of alumina–tungsten carbide nanocomposite was investigated. Characteristics of the densification and sintering were analyzed considering both the nano-size particle starting powders and the processing stages. Different heating rates were generated during densification and consolidation with a maximal load was applied only after a temperature of 1000 °C was reached. Due to the varying dominance of different physical processes affecting the grains, appropriate heating rates and pressure at different stages ensured that a structure with submicron grains was obtained. With directly applied alternating current, it was found that the proportion Al2O3 (50 wt.%)–WC provided the highest fracture toughness, and a sintering temperature above 1600 °C was found to be disadvantageous. High heating rates and a short sintering time enabled the process to be completed in 12 min, saving energy and time.

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“…This feature is associated with the intensification of grain boundary diffusion [27] which results in the predominance of compaction processes over the processes of ceramic grain growth due to the removal of open pores. It is known that the change in heating rate leads to an increase in the temperature gradient inside the powder being sintered and creating a local mismatch of thermal expansion coefficients [28,29]. Besides, a significant discrepancy between the coefficients of thermal expansion of zirconium oxide and alumina powder particles leads to dislocations motion to the boundaries being formed raising their free volume and grain boundary diffusion coefficient.…”

Section: The Effect Of Additives On Structure and Properties Of Materials Based On Zirconium Dioxide Nanopowdermentioning

confidence: 99%

Revealing specific features of structure formation in composites based on nanopowders of synthesized zirconium dioxide

Gevorkyan

Nerubatskyi

Chyshkala

et al. 2021

EEJET

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Peculiarities of formation of microstructure in composites based on chemically synthesized zirconium nanopowders obtained by the method of decomposition from fluoride salts were considered. Hydrofluoric acid, concentrated nitric acid, aqueous ammonia solution, metallic zirconium, and polyvinyl alcohol were used. It was established that the reduction of porosity in nanopowders in the sintering process is the main problem in the formation of high-density materials. Analysis of various initial nanopowders, their morphology, and features of sintering by the method of hot pressing with direct transmission of electric current was made. Peculiarities of obtaining the composites based on them with the addition of Al2O3 nanopowders applying the electric sintering method were considered. It was shown that the increase in the content of alumina nano additives leads to an increase in strength and crack resistance of the samples due to simultaneous inhibition of abnormal grain growth and formation of a finer structure with a high content of tetragonal phase. The influence of sintering modes on the formation of the microstructure of zirconium nanopowders has been studied for different contents of alumina additives. Electric current promotes the surface activity of nanopowders and its variable value promotes partial fragmentation of agglomerated grains thus affecting the composite structure. Physical-mechanical properties of the obtained samples, optimal compositions of mixtures, and possibilities of improving some parameters were determined. It was found that nanopowders of zirconium dioxide obtained by the method of decomposition from fluoride salts are quite suitable for the production of composite materials with high physical and mechanical properties. They can compete with imported analogs and enable obtaining of crack resistance of 7.8 MPa·m1/2 and strength of 820 MPa.

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Feasibility of Cobalt-Free Nanostructured WC Cutting Inserts for Machining of a TiC/Fe Composite

Cited by 21 publications

References 31 publications

Peculiarities of the Phase Formation during Electroconsolidation of Al2O3–SiO2–ZrO2 Powders Mixtures

Peculiarities of the Phase Formation during Electroconsolidation of Al2O3–SiO2–ZrO2 Powders Mixtures

Analysis of the Electroconsolidation Process of Fine-Dispersed Structures Out of Hot Pressed Al2O3–WC Nanopowders

Revealing specific features of structure formation in composites based on nanopowders of synthesized zirconium dioxide

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