CURRENT STATE OF THE SCIENTIFIC PROBLEM OF WC–Co HARD ALLOYS SURFACE HARDENING (REVIEW)

Осколкова, Т. Н.; Глезер, А. М.

doi:10.17073/0368-0797-2017-12-980-991

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…As a result of nano identification of a hard alloy with an ionic-plasma (Ti, Zr)N coating it was found that this coating was super-hard with nanohardness of 38000 -38500 MPa (Fig. 3) [8].…”

Section: Resultsmentioning

confidence: 98%

Wear-Resistant Coating on Hard Alloy

Oskolkova

2015

AMM

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In this research new data on the effect of zirconium as an ingredient of the ionic-plasma (Ti, Zr)N coating which is spread on the alloy VK10 KS was obtained. It was found that the introduction of zirconium into the coating composition led to an increase in nanohardness by 23 % up to 38500 MPa and in Young’s modulus – by 67 %, which indicated an increase of energy of atomic bonds and in strength of materials. Also, it led to an increase in an antifriction ability and decrease in the friction constant of the coating up to μ = 0,07, a satisfactory adhesive strength of coating, i.e. in general improved the service features of the whole alloy.

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“…As a result of nano identification of a hard alloy with an ionic-plasma (Ti, Zr)N coating it was found that this coating was super-hard with nanohardness of 38000 -38500 MPa (Fig. 3) [8].…”

Section: Resultsmentioning

confidence: 98%

Wear-Resistant Coating on Hard Alloy

Oskolkova

2015

AMM

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Influence of pulse-plasma modification with titanium and silicon carbide of the surface of hard VK10KS alloy on its structure and properties

Осколкова¹,

Симачев²

2021

Izv. vysš. učebn. zaved., Čern. metall.

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Electro-explosive alloying as a method of pulse-plasma treatment consists in accumulation of energy by a battery of pulsed capacitors and its subsequent discharge for 100 μs through a conductor in form of titanium foil with silicon carbide powder, while conductor is under explosive destruction. Method of electro-explosive alloying of tungsten-cobalt hard alloy includes melting of surface and its saturation with explosion products, followed by self-hardening by removing heat deep into the material and environment. On the surface of VK10KS hard alloy, the coating was obtained with thickness of up to 15 – 20 microns with nanohardness of 26,000 MPa. Using X-ray phase analysis and scanning electron microscopy, it has been established that new phases of TiC, W2C, (W, Ti)C1 – x , WSi2 with high hardness were formed in the surface layer. As a result, friction coefficient decreased to 0.18 compared to the initial 0.41. Investigations with transmission electron microscopy have revealed changes during electro-explosive alloying that occur in surface carbide and near-surface cobalt phases. Dislocations accumulations were found in the carbide phase. In cobalt binder, deformation bands (slip bands), single dislocations, and finely dispersed precipitates of tungsten carbides were revealed. This change can be explained by stabilization of cubic modification of cobalt, crystal lattice of which has a large number of slip planes upon deformation and greater ability to harden in comparison with hexagonal modification of cobalt. Additional alloying with cobalt binder in heat affected zone after pulse-plasma treatment have a positive effect on the service life of tungsten-cobalt hard alloys as a whole due to their stabilization.

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Influence of pulse-plasma modification of VK10KS solid alloy surface by titanium and boron on its structure and properties

Осколкова

Симачев

2020

Izv. vysš. učebn. zaved., Čern. metall.

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Modification of the surface of VK10KS solid alloy with titanium alongside with boron by the method of pulse-plasma exposure (electro-explosive alloying) is considered. In this case, a superhard (27,500 MPa nanohardness) layer is formed with a thickness of 2.0 – 2.5 μm and a low (μ = 0.10) friction coefficient compared to the friction coefficient of a hard alloy in the sintered state (μ = 0.41). This layer consists of finely dispersed high-hard phases TiB2, (Ti, W)C, W2C (according to scanning, transmission electron microscopy and X-ray phase analysis). Below is a hardened (with a nanohardness of 17,000 MPa) surface layer (heat affected zone) 10 – 15 μm thick, identified by W2C and WC carbides and alloyed with a cobalt binder. This layer smoothly passes into the base. By profilometric studies it was established that after electroexplosive alloying with titanium and boron, the roughness increases (Ra = 2.00 μm) compared to the initial one (Ra = 1.32 μm), but remains within the specifications (Ra = 2.50 μm). The authors have revealed changes that occur in the surface carbide and near-surface cobalt phases during electroexplosive alloying. In the carbide phase, accumulations of dislocations were indicated. In the cobalt binder, deformation bands (slip bands), single dislocations, and also finely dispersed tungsten carbide precipitates were found. This change can be explained by stabilization of the cubic modification of cobalt, the crystal lattice of which has a large number of slip planes during deformation and a greater ability to harden compared to the hexagonal modification of cobalt. Additional alloying with a cobalt binder will positively affect the operational stability of tungsten carbide alloys as a whole due to their stabilization.

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CURRENT STATE OF THE SCIENTIFIC PROBLEM OF WC–Co HARD ALLOYS SURFACE HARDENING (REVIEW)

Cited by 3 publications

References 8 publications

Wear-Resistant Coating on Hard Alloy

Wear-Resistant Coating on Hard Alloy

Influence of pulse-plasma modification with titanium and silicon carbide of the surface of hard VK10KS alloy on its structure and properties

Influence of pulse-plasma modification of VK10KS solid alloy surface by titanium and boron on its structure and properties

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