Features of structure formation of the surface layer in the course of electroexplosive alloying tungsten carbide hard alloy

Surface preparation is a prerequisite for ensuring the required properties of a diamond film obtained by gas-phase deposition. The paper considers the effect of temperature and concentration of the etchant CuSO4 on the structural and phase composition of the surface of hard-alloy materials. The structural and phase composition of a continuous polycrystalline diamond film at its growth stages was also studied. Adhesion of the obtained diamond films to the surface of carbide materials was qualitatively determined. It has been established that surface treatment of a hard alloy in a CuSO4 solution at a temperature t = 23 °C leads to unequal removal of the cobalt bond with chipping of WC grains and the formation of a porous structure in the surface layer of the WC–6%Co alloy. The treatment with an etchant CuSO4 at t = –2 °С ensures uniform etching of the Co-bond along the WC grain boundaries and the formation of a chemically uniform surface. The orientational growth and adhesion of the diamond film depend on the elemental composition of the surface of the WC–Co alloy after treatment with a CuSO4 solution. If the treatment was carried out at a tsolution = 23 °C, then during the synthesis of the diamond film, the removal of copper from the defective surface layer of WC is difficult. This provides the multidirectional growth of diamond crystals in the film in two directions: <111> and <110>, which causes critical biaxial compressive stresses (2,5 GPa) and leads to low adhesion of the film to the surface of the hard alloy. If the treatment was carried out at tsolution = –2 °C, then the orientational growth of diamond crystals in the film occurs in one preferential crystallographic direction <111>. It reduces the biaxial compressive stresses (1,7 GPa) and increases the adhesive adhesion of the film to the surface of the hard alloy . The structure defect, calculated from the ratio of the lines of integrated intensities I1333 / I1580 using the Raman spectroscopy, decreases with concentration growth for negative temperatures and increases for positive ones of CuSO4 solution during surface preparation.

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STRUCTURE FORMATION OF α-Fe THIN SURFACE LAYER WITH GLOW DISCHARGE PLASMA

Bulletin of Bryansk state technical university ◽

10.30987/article_5cda64cd74fc24.33017288 ◽

2019 ◽

Vol 2019 (5) ◽

pp. 44-50

Author(s):

Владимир Логвин ◽

Vladimir Logvin ◽

Ирина Терешко ◽

Irina Tereshko ◽

Сергей Шептунов ◽

...

Keyword(s):

Surface Layer ◽

Glow Discharge ◽

Structure Formation ◽

Discharge Plasma ◽

Glow Discharge Plasma ◽

Thin Surface Layer ◽

Technological Environment ◽

New Methods ◽

Energy Impact ◽

Structure Changes

A theory explaining a structure formation in a thin surface layer of material after a low-energy impact of glow discharge plasma with the purpose of the development of new methods, technologies and automated devices for the formation of automated technological environment is developed. An impact of lowenergy processing in a glow discharge upon dislocation structure changes in a thin surface layer by the example of annealed α-Fe is investigated.

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Structure Formation of Polycarbide-Based TiC-VC(NbC)-WC/nano WC Hard Alloys

Boundary Field Problems and Computer Simulation ◽

10.7250/bfpcs.2018.005 ◽

2019 ◽

Vol 57 ◽

pp. 35-40 ◽

Cited By ~ 2

Author(s):

Liudmyla Bodrova ◽

Halyna Kramar ◽

Yaroslav Kovalchuk ◽

Sergiy Marynenko ◽

Ihor Koval

Keyword(s):

Chemical Composition ◽

Tungsten Carbide ◽

Optical Microscopy ◽

Structure Formation ◽

Sintering Temperature ◽

Xrd Analysis ◽

Hard Alloys ◽

Alloying Additions ◽

The Core

The process of structure formation in the alloys of the system TiC-VC(NbC)-NiCr with the alloying additions of the fine or nano WC, depending on the chemical composition and sintering temperature using the optical microscopy, SEM and XRD analysis, is investigated in this paper. The core/rim structure alloys were found irrespective of the amount of tungsten carbide additions. The research suggests that the adding of nano WC causes decrease in carbide grains, redistribution of the elements in the core and rim, and decrease in sintering temperature by 50–100 °С. Tika pētīts struktūru veidošanas process sakausējumos TiC-VC(NbC)-NiCr ar smalku vai nano WC sakausējuma papildinājumiem atkarībā no ķīmiskā sastāva un saķepināšanas temperatūras, izmantojot optisko mikroskopiju, SEM un XRD analīzi. Centru/aptvērumu struktūras sakausējumi tika konstatēti neatkarīgi no volframa karbīda piedevu daudzuma. Pētījums liecina, ka nano WC pievienošana samazina karbīda graudus, elementu pārdali centros un aptvērumos, kā arī notiek saķepināšanās temperatūras samazināšanās par 50–100° С.

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Special features of structure formation in and properties of the surface layer of steel irradiated by a beam of relativistic electrons

Metal Science and Heat Treatment ◽

10.1007/bf02469069 ◽

1997 ◽

Vol 39 (4) ◽

pp. 146-150 ◽

Cited By ~ 2

Author(s):

I. M. Poletika ◽

M. D. Borisov ◽

G. V. Kraev ◽

A. F. Vaisman ◽

M. G. Golkovskii

Keyword(s):

Surface Layer ◽

Structure Formation ◽

Relativistic Electrons

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Laser Alloying with WC Ceramic Powder in Hot Work Tool Steel Using a High Power Diode Laser (HPDL)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.15-17.193 ◽

2006 ◽

Vol 15-17 ◽

pp. 193-198 ◽

Cited By ~ 9

Author(s):

Marek Piec ◽

Leszek Adam Dobrzański ◽

Krzysztof Labisz ◽

Ewa Jonda ◽

Andrzej Klimpel

Keyword(s):

Surface Layer ◽

Tungsten Carbide ◽

Diode Laser ◽

Tool Steel ◽

High Power ◽

Feed Rate ◽

Powder Feed Rate ◽

Powder Feed ◽

Power Diode ◽

High Power Diode Laser

Investigations include alloying the X38CrMoV5-3 hot-work tool steel surface layer with the tungsten carbide, using the high power diode laser (HPDL). The tungsten carbide ceramic particles of the medium grain size according to FSSS = 50 /m were introduced using the rotor conveyer to improve the properties of the surface layer. The powder feed rate was set at the steady level of 8.64g/min. Remelting and alloying were carried out several times in the laser power range of 1.2 – 2.3 kW in the remelting/alloying, alloying/remelting sequences. The structural mechanism was determined of gradient layer development, effect was studied of alloying parameters, gas protection method, and powder feed rate on its mechanical properties, and especially on its hardness, abrasive wear resistance, and roughness. Structure changes were revealed consisting, in particular, in its refining, and also hardness and microhardness changes in comparizon to the nonremelted steel. Examination results obtained with the EDX microanalysis, surface and linear analysis of the chemical composition, as well as the X-ray qualitative phase analysis are presented.

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