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

This work was aimed to smelt high-entropy alloys (HEAs) based on inexpensive and common metallic elements using iron-based alloys, ligatures, commercially pure metals and study HEAs’ phase structure. High-entropy alloys of the FeNiCrCuAl system were smelted in air using induction furnace in a crucible with a rammed neutral lining made of aluminum and magnesium oxides. Elements of Fe, Ni, Cr, Cu, Al were added by way of high-alloyed cast iron or stainless-steel grade X10CrNiTi18-10 (EN 1.4541), low-carbon ferrochrome of industrial grade FeCr70C1, binary Cu-33Al ligature, tough-pitch copper and semi-finished nickel. The investigated alloys were prepared by lost foam and sand mold casting methods. A study of the microstructure showed the presence of rounded shape branches of dendrites, copper-rich interdendritic space and high-chromium carbides in the structure of samples. The phase composition of the as-cast FeNiCrCuAl alloys was represented by several phases: ordered solid solution with primitive cubic lattice of type B2, solid solutions with BCC and FCC lattices and complex carbides (FeCr)₇C₃.

This work presents a brief overview of the essence, principles and technological features of reactive electrospark processing (RESP), based on a simple, economical and ecological method – electrospark deposition (ESD), which avoids many of the disadvantages inherent in other existing methods. This treatment can optimize the physicochemical properties of the substrate surface and improve the structure, hardness and wear resistance. The application of RESP technology in surface modification of titanium alloys is considered. Research results, including those of the authors of this work, are presented, which demonstrate the possibilities of RESP for reducing
roughness and surface defects and for the synthesis of new phases and ultrafine structures that are not present in the electrode and substrate. The effect of RESP technology on the wear resistance of titanium and titanium alloys is shown. The main dependences of the quality and properties of the treated surfaces on the process parameters are identified, and ways to form reaction phases, to avoid and remove surface defects and to obtain “in-situ” new intermetallic and wear-resistant compounds are presented. The possibilities and prospects for the use of RESP to improve the surface characteristics and properties of titanium and its alloys are indicated.

The research of the technology of obtaining new copper-ferrochrome composite material has been done. The results of its structure and properties analysis are presented. The material structure consists of the copper base, non-dissolved coarse inclusions of ferrochrome, diffused zones, forming around these inclusions and phases, having formed in the place of completely dissolved inclusions of ferrochrome fine particles. The material has good mechanical properties and a high wear resistance due to the formed solid solutions of the carbides in the copper.

Compositions of the products of the electrolysis of melts based on a eutectic mixture of sodium chloride–lithium fluoride and sodium tungstate, which contains molybdenum (VI) and tungsten (VI) oxides, molybdates, tungstates, and carbonates of lithium or sodium, are investigated. It is shown that, depending on the content of melt components, the products of electrolysis are carbon, molybdenum, tungsten, and their bronzes and carbides. The conditions of the deposition of galvanic coatings of molybdenum and tungsten carbides on carbon, nickel, and copper matrices are determined.

This paper researches the influence of the cutting edge’s geometry and coating on its durability. Four types of edge geometry and two types of coating are studied as well as the influence of abrasive material on production of the chamfer.