Pareniuk O. Obtaining special copper alloys, strengthened by ultra-disperse FeCrC based inclusions, formed in the melt under the action of an alternating electromagnetic field

The dissertation work is devoted to the solution of the actual scientific and technical task: development of the melting technology in the micro-emulsion state special copper alloy with FeCrC addition on the theoretical basis, particularly, determination of the peculiarities of the effect of variable electromagnetic field on the melt, taking into account the ideas about the appearance of magnetohydrodynamic micro-currents around the additive, due to different electromagnetic properties of the ligature and the basis of the alloy in an induction crucible furnace. It is experimentally confirmed that due to the structural heterogeneity of the additive, the electric current generated in the melt by an alternating electromagnetic field is redistributed, which causes a local concentration of the electric current density in the more electrically conductive phase of the additive, increases the heat emission in it, and contributes to the appearance of channels through which the matrix melt penetrates and wedges the additive, thus accelerating its dispersion. The conditions of dispersion of the additive to micron sizes at the initial stage of its smelting with the copper base, including the formation of an induction furnace in the crucible of a local area of high electrical current density and the retention of an alloying additive in this area, which significantly intensifies the process of its dissolution, are determined. The influence of the additive concentration on the size of inclusions is determined and rational modes of formation of frozen microemulsion in the cast structure of the alloy cooling and hardening are established. On the basis of the established dependencies, a new MGD technology was created, which allows to fix in a solid-state the inclusion of ultra-disperse dimensions (≤1 micron) at a high density of their homogeneous distribution and to reduce electricity consumption by 3 kW∙h/kg during the melting of the dispersion hardened copper alloy. The current collector pantograph inserts of DC electric locomotives are made of such a material have effectively balanced properties (relative specific electrical conductivity of the insert and the contact wire is 0,9 and the ratio of the hardness of the working layer of the insert and the contact wire is 0,8), which provides an increase in the mileage of research pantograph inserts in freight and passenger traffic as compared to the serial inserts of the PCD type by 25%.