Structure and characteristics of a thin-layer "aluminum - carbon nanotubes" sandwich structure

The study describes a way to produce thin-layer sandwich structures containing layers of aluminum foil and an interlayer filler of carbon nanotubes (CNTs). To obtain a homogeneous structure of the composite, induction heat treatment was used combined with a device providing primary compression of the assembly. To determine the functional characteristics of sandwich structures, the homogeneity of their microstructure and surface conductivity were studied. It was found that the use of CNTs allowed increasing the surface conductivity by a factor of 8.3–9.5 compared to the sandwich structure without filler.

Experimental study of the simultaneous effects of severe plastic deformation and secondary radial strain on copper

Due to the widespread use of copper wires in electrical power transmission, the need for raw materials with a homogeneous structure and high strength while maintaining their conductive properties is of high importance. The present study investigates the production of copper wire with improved mechanical properties and homogeneous microstructure due to its nanometre-sized structure. Therefore, the commercial pure copper specimens were subjected to severe plastic deformation (SPD) by means of equal channel angular pressing (ECAP) during four steps at ambient temperature. Due to the creation of a structure with elongated grains in the ECAP process, the deformed specimens were subjected to the direct extrusion operations; thus, a more homogeneous structure was created in them due to the appearance of a secondary radial strain. The obtained results indicate that by applying the simultaneous effects of SPD and direct extrusion on the microstructure, the mechanical properties such as strength and hardness have improved significantly, while the electrical conductivity of pure copper decreased slightly. The outcome can be used as an alternative to current methods for producing high-strength copper wires with suitable electrical conductivity properties.

Microalloying effects on structure-forming processes during hot plastic deformation

The kinetics of austenite grains' growth upon heating has been investigated, and the processes of dynamic and static recrystallization occurring under different modes of plastic deformation (reduction pattern, deformation temperature) of high-strength steels with various microalloying complexes have been studied. The research made it possible to reveal the thermal deformation conditions for the formation of a finely dispersed homogeneous structure of steel. Technological recommendations have been developed for the production of high-strength steels depending on their microalloying (vanadium, niobium).

IMPROVING THE HARDENABILITY OF MASSIVE FORGINGS FROM ALLOYS OF THE Al–Zn–Mg–Cu SYSTEM BY BALANCED ALLOYING WITH ZINC AND MAGNESIUM

The paper presents the results of studies of the influence of the Zn:Mg ratio on the hardenability, structure and complex of mechanical and corrosive characteristics of forgings with 150 mm thickness made of alloys based on Al–Zn–Mg–Cu system, manufactured in the production conditions of metallurgical plants of JSC AMR and Public Corporation “KUMZ”. It has been determined that an alloy of the Al–Zn–Mg–Cu system with Zn:Mg ratio of not less than 4,1:1 and copper mass content of not more than 1.2% has a higher hardenability compared to the 1933 alloy of standard composition, which ensures homogeneous structure and indicators of mechanical and corrosion properties over the thickness of semi-finished pro-ducts; in metallurgical industry at the stage of manufacturing this allows reducing the residual quenching stresses in massive forgings by means of straightening by reduction in an as-quenched state.

Egg whites-derived carbon/magnetic nanoparticles/water-soluble graphene oxide composite with homogeneous structure as an excellent electromagnetic wave absorber

An egg white-derived carbon/magnetic nanoparticles/water-soluble graphene oxide composite absorber (EWC/MNPs/WSGO) was specially designed and synthesized via a facile sol-gel process with subsequent high-temperature pyrolysis. Magnetic nanoparticles (MNPs) were used to...