International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The physic-technological basis for fabrication of bulk rods and plates of amorphous, amorphous-nanocrystalline and 100% nanocrystalline alloys at melt cooling rates from 80 to 3200 K/s with crystal sizes from 10 to 50 nm has been developed. The multiphase structure formed in the initial bulk samples, as well as in the process of nanocrystallization of amorphous ribbons, is characterized by record microhardness values of 17-22 GPa. Amorphous powders (20-100 μm) of Fe55Ni8Co6Mo4Cr2V1Al2P9C6B5Si2 and Fe61.37Co6.84Cr3.78V0.85W0.82Mo1.06Nb0.85B19.87C1.99Si2.57 alloys are used to create a wear-resistant coating on structural stainless steels and low-carbon St3 by the gas-thermal “cold” method » sputtering and subsequent melting of the applied layer.The values of microhardness (Hμ) of nano-coatings significantly exceed the microhardness of all known tool steels. Examples of technology transfer and practical using of developed amorphous and nanocrystalline alloys are presented.

In this work, the method of backscattered electron diffraction (EBSD) and transmission electron microscopy (TEM) was used for microstructural analysis of the improved VT8M-1 alloy (Ti-5.7 Al-3.8 Mo-1.2 Zr-1.3 Sn) subjected to equal-channel angular pressing (ECAP) and rotary forging (RF). It was found that the process of globularization induced during deformation processing is regulated by the conventional boundary-splitting mechanism. It was shown that an orientation relation is established between the spheroidized a – and bphases. This result is achieved due to the high activity of dislocation sliding at the boundary of the a-and b-phases. The thermal stability of the VT8M-1 alloy with an ultrafine-grained (UFG) structure is s -term (up to 500 hours) annealing the UFG structure is thermally stable. The mechanical properties and the effect of annealing on the microstructure are discussed. It is shown that particles of the Ti-Zr-Si system are isolated at the interphase boundaries.

This work investigate electromagnetic and thermal properties of poly(lactic) acid-based composites with graphene nanoplates (GNP) and multiwalled carbon nanotubes (MWCNTs), produced by solution blending method. It was found that the MWCNT carbon nanotubes are an effective filler for both absorption and reflection of electromagnetic waves in the GHz and THz frequency domains. The higher aspect ratio of carbon nanotubes, compared to industrial MWCNT, is the cause of better electromagnetic characteristics of nanocomposites prepared by solution blending method (SB). The DSC analysis of the samples shows that the glass transition is around 60oC, followed by cold crystallization with enthalpy and melting temperature around 150oC. The TGA analysis show, that the thermal stability of PLA polymer is improved by addition of 6% MWCNTs and GNP.

The hardening and austenite stability as a result of nitrogen alloying steel type of Cr₁₈Ni₁₀ in the temperature range, which is usual for the application of such steels as corrosion-resistant structural heat-resistant and/or cryogenic ones was studied. It is shown that the nitrogen alloying is perspective for strengthening and increasing of stability of austenitic stainless steels. Additional strengthening due to the preliminary cold or warm deformation hardening increases a tendency to the martensite formation under load, which limits the operating temperature of these steels. High-strength non-magnetic nitrogen-alloyed steels on the base of Cr₁₈Ni₁₀ steels containing up to 0.22 % of nitrogen are suitable for cryogenic application of non-deformed articles only. Otherwise, a strain-induced martensite will always form in them at temperatures below -70 °С. High strength, ductility and toughness of these steels can be achieved simultaneously only as a result of the TRIP-effect or fine-grained structure formation.