UDC 669.017.3
G. S. Oleinyk1, *, A. V. Kotko1, M. I. Danylenko1, P. M. Silenko1, Yu. M. Solonin1, O. F. Pylypchuk1, A. I. Danylenko1, T. I. Tomila1, O. O. Bochechka2, **, O. I. Cherniyenko2, O. V. Kushch2
1I. M. Frantsevich Institute for Problems of Materials Science, NAS of Ukraine, Kyiv, Ukraine
2V. M. Bakul Institute for Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*oleynik@ipms.kiev.ua
**bochechka@ism.kiev.ua
Structural transformations in boron carboxynitride during synthesis and sintering at high pressure and high temperature (pp. 3-14)
The results of an electron microscopic study of the structure formation of boron carboxynitride (BNCO) during its synthesis based on the starting boron oxide and melamine in the form of a powder and a coating on single-crystal diamond particles are presented. Structural studies were carried out using transmission electron microscopy methods, including high resolution in combination with elemental microanalysis. It was established that during the synthesis of a single-phase powder in the interval T = 700–1200 °C, the main component is turbostratic BNCO of varying degrees of ordering. At a temperature of 1200 °C, the formation of an ordered shape occurs with the formation of inclusions in the particles with sizes up to 100 nm in the form of nanotubes, onions and prisms. BNCO deposition on diamond particles is monolithic and has continuous interfaces with diamond. During sintering (p = 7.7 GPa, T = 1700 °C) of single-phase BNCO and in the composition with diamond (both coated particles and in the form of powder), the formation of a sphalerite phase with a graphite-like residue occurs. Only in the case of using diamond powders with a grain size of 0.1/0, the sphalerite phase is the main component in the sintered samples.
Keywords: boron carboxynitride, powder, diamond, particle, turbostratic, sintering.
UDC 620.22-621.921.34
V. A. Mechnyk1, *, M. O. Bondarenko1, T. O. Prikhna1, V. M. Kolodnitsky1, **, V. E. Moshchil1, V. V. Strelchuk2, A. S. Nikolenko2, E. S. Gevorkyan3, V. A. Chyshkala4
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2V. E. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, Ukraine
3Ukrainian State University of Railway Transport, Kharkiv, Ukraine
4V. N. Karazin Kharkiv National University,
Kharkiv, Ukraine
*vlad.me4nik@ukr.net
**vasylkolod56@gmail.com
Phase formation and physical and mechanical properties of Fe‒Cu–Ni‒Sn–VN composites sintered by vacuum hot pressing for diamond stone-cutting tools (pp. 15-27)
The effect of the concentration of vanadium nitride additive (in the range from 0 to 10% (by weight)) on the phase formation, hardness and fracture toughness of composite diamond-containing materials based on 51Fe–32Cu–9Ni–8Sn matrix formed by cold pressing followed by vacuum hot pressing was investigated. It was found that the addition of 10% vanadium nitride to the 51Fe–32Cu–9Ni–8Sn composite is accompanied by an increase in hardness from 3.86 to 8.58 GPa with a slight decrease in fracture toughness from 5.55 to 4.76 MPa∙m1/2. The dependence of hardness on the concentration of vanadium nitride H (CVN) has two characteristic regions that differ in the angle of inclination. In the range 0 < CVN < 4%, the hardness increases slightly (from 3.86 to 5.26 GPa), and for CVN > 4%, the hardness increases significantly and the grain size decreases. It is shown that the mentioned indicators change due to the dispersion mechanism of strengthening and modification of the structure (reduction of the average size of matrix phases, formation of new phases (Fe3Ni)0.5, Cu3Fe17, isolation of primary and secondary phases of vanadium nitride) and the phase composition of composites.
Keywords: composite, iron, copper, nickel, tin, vanadium nitride, composition, concentration, vacuum hot pressing, structure, hardness, fracture toughness.
UDC 666.539.3/6 (045)
A. G. Dovgal*, V. V. Varyukhno, L. B. Priymak
National Aviation University, Kyiv, Ukraine
*kalibr201@ukr.net
The influence of structure formation of Al2O3–C composites with different graphite contents on their mechanical properties (pp. 28-34)
The influence of composition and activating impurities on the structure of the Al2O3–C composite was investigated. Porosity and morphological features of the structure were studied. The following physicomechanical properties of the obtained samples were investigated, such as bending strength and hardness. The optimal values of these characteristics were established in relation to the composition and technological modes of obtaining.
Keywords: alundum, graphite, corundum, strength, hardness, density, porosity.
UDC 621.763
S. V. Lytovchenko1, E. S. Gevorkyan2, *, V. P. Nerubatsky2, V. O. Chyshkala1, L. V. Voloshyna2
1Kharkiv National University named after V. N. Karazin, Kharkiv, Ukraine
2Ukrainian State University of Railway Transport, Kharkiv, Ukraine
*edsgev@gmail.com
Study of the regularities of formation and structure formation of compacted and multicomponent silicide composites (pp. 35-52)
Technologies for obtaining carbide and multielement powders from scrap hard alloys and tungsten anhydride in laboratory conditions for further use in forming eutectic coatings. The temperature-time parameters of the process of obtaining powders of the required chemical composition were determined. It was established that in the case of introducing boron and silicon additives into these powders in quantities corresponding to the eutectic compositions, it is possible to obtain compositions with a melting point regulated in the range of 1000–1200 °C. Slip mixtures were produced based on powders of the Ni–Si–B and Ni–Cr–Si–B compositions with reinforcing additives of industrial and laboratory-synthesized refractory silicides and carbides. Eutectic coatings with a microhardness of the solid component of 18–26 GPa and a plastic matrix of 11–15 GPa were obtained by melting slip mixtures on steel and molybdenum substrates. Comparison of structural characteristics and properties of coatings showed that high-speed formation of coatings by fusion allows to obtain a protective layer of the required thickness and prevents excessive embrittlement of the base due to the formation of boride phases. It was established that molybdenum disilicide additives in an amount of up to 50% (by weight) increase the uniformity of the coating without reducing its hardness. The coating is characterized by high corrosion resistance to temperatures of ~ 1000 °C.
Keywords: silicide composites, consolidation, thermal conductivity, multi-element powders, reinforcing additives, slip mixtures, eutectic coatings.
UDC 675.92.026.79:621.921.34:541.124.7
Qiquan Li1, Qi Zhang1, Baoyan Liang1, Wangxi Zhang1, Li Yang2, *
1Materials and Chemical Engineering School, Zhongyuan University of Technology, Zhengzhou, P.R. China
2Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, P.R. China
*357827404@qq.com
Coating on the surface of diamond particles by thermal explosion reaction method (pp. 53-60)
Using a Mn–Al–B mixture as a raw material, a multi-element composite coating based on Mn2AlB2 was obtained by thermal explosion synthesis technology on the surface of diamond. The effect of different Al contents on the phase composition and microstructure of the bond and the coating was studied. X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy were used to analyze the phase composition and morphology of the samples obtained by thermal explosion. It was shown that the Mn–Al–B–diamond compacts as a result of the reaction during thermal explosion are transformed into porous loose blocks. The bonds obtained after separation mainly consisted of Mn2AlB2. Other by-products, such as Al, MnB, MnB2, Al78Mn23, Al8Mn5, and Mn2AlC, were also obtained. The coating covers the diamond surface well, and its structure consisted of nano- and micrograins.
Keywords: coating, diamond, thermal explosion reaction.
UDC 621.791.927.55
C. S. Samotugin1, , V. I. Lavrinenko2, *, Yu. S. Samotugina1, I. I. Pirch1, O. O. Bezumova1
1Pryazovsky State Technical University, Ministry of Education and Science of Ukraine, Mariupol, Ukraine
2V. M. Bakuly Institute of Superhard Materials, National Academy of Sciences of Ukraine, Kyiv, Ukraine
*zaplazmu@gmail.com
**lavrinenko@ism.kiev.ua
Technological principles of plasma nanostructuring of tool composites for tools with a complex surface shape (pp. 61-72)
Based on studies of the structure and properties of tool steels (P6M5, Kh12M) and hard alloy VK8 on the example of thread-forming tools (cutters, combs, rollers), the possibilities of obtaining a nanocrystalline structure of the modified zone during surface treatment with a highly concentrated plasma jet were established. The formation of nanodispersed particles of martensite (in steels) and carbides (in steels and hard alloys) is due to an increase in the cooling rate and the implementation of the “barrier” effect during dispersion hardening under conditions of rapid crystallization (processing with micro-melting) or rapid quenching (processing without melting). The effect of plasma treatment on the cutting surface of grinding wheels with NTM on metal bonds was studied. A change in the elemental composition of the surface, the presence of a film oxygen-containing coating on the bond and NTM grains, and a change in the hardness of the bond surface were shown.
Keywords: plasma surface modification, tool steel, hard alloy, NTM wheels, complex-shaped surface.
UDC 621.921.34:666.233.08374
G. A. Petasyuk, Yu. V. Sirota*
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*petasyuk@ukr.net
**yatoris@gmail.com
Comparative analysis of the shape similarity of the projection of grains of grinding powders of synthetic and natural technical diamond and their uniformity according to this characteristic (pp. 73-84)
A review of publications on the comparative study of morphometric characteristics, technological and physical properties of powders of synthetic and natural technical diamond was carried out. Applied and methodological aspects of the projection of grains of diamond powders as the most acceptable and accessible for assessing the quality of such powders, the 3D expression of their shape were analyzed. According to the results of the review, it was emphasized that the characteristics of the shape similarity of the projection of grains of such powders, methods for identifying the shape of the projection of their grains have great practical significance for abrasive processing. A comparative analysis of the shape similarity of the projection of grains of grinding powders of synthetic and natural technical diamond and their uniformity according to this characteristic as an important quality characteristic is carried out. The results of determining the shape similarity characteristics are presented, and the trend of their change is established.
Keywords: synthetic diamond, natural diamond, grain, projection, shape similarity, uniformity, identification, relative error.
UDC 621.9.025.77:621.95:546.26
Jinyang Xu*, Linfeng Li, Tieyu Lin, Ming Chen
State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, P.R. China
*xujinyang@sjtu.edu.cn
Evaluation of diamond-coated tools in drilling high-strength carbon fiber reinforced polymers (CFRP) (pp. 85-96)
High-strength carbon fiber reinforced polymers (CFRP) are advanced superhard structural materials that are widely used in modern aerospace industry, but they are difficult to machine. This paper aims to study the effectiveness of special diamond-coated tools on the machining properties of high-strength CFRP composites. The investigated CFRP sample was a multi-directional polymer-based composite laminate made of T700 high-strength carbon fibers and FRD-YZR-03 epoxy resin. The effectiveness of diamond tools in cutting high-strength CFRP was thoroughly studied in terms of workpiece reaction, surface defect status and quality status of the cut product. The results show that the tool geometry significantly affects the cutting behavior of the composite, and the stepped drill outperforms the candlestick tool due to the stepped geometry, which minimizes the hard contact interaction with the solid CFRP composite workpiece during the chip separation process. The CFRP composite is likely to cause serious surface defects due to its extremely high strength and modulus despite the use of diamond-coated tools. Moreover, a well-designed geometric modification of the diamond tool can significantly improve the surface quality of the composite product.
Keywords: high-strength composites, diamond-coated tools, machinability, delamination damage.
UDC 621.623
Yu. D. Filatov
V. M. Bakul Institute of Superhard Materials, NASU, Kyiv, Ukraine
filatov@ism.kiev.ua
Relationship of transfer coefficients with transfer energy during polishing of non-metallic materials (pp. 97-100)
As a result of the study of the mechanism of polishing of non-metallic materials using dispersed systems of micro- and nano-particles, the law of changes in the ratio of the volumetric wear coefficient to the thermal conductivity coefficient of the processed material or polishing powder particles depending on their transfer energy and specific heat capacity was generalized.
Keywords: energy transfer, transfer coefficients, polishing.