• TECHNOLOGIES

    The impact of high voltage electric discharge treatment in ethanol on the dispersity and phase composition of Cu – Al powder mixture

    Machines. Technologies. Materials., Vol. 18 (2024), Issue 6, pg(s) 185-188

    Studies of the impact of high voltage electric discharge (HVED) treatment on the dispersion and phase composition of 87,5 % Al + 12,5 % Cu powder system were performed. It was shown that HVED treatment in ethanol with specific treatment energy of 5 MJ/kg leads to the decrease of mean diameter of treated powder from 15 to 11 μm, and the increase of specific treatment energy to 20 MJ/kg leads to the decrease of mean diameter of treated powder from 15 to 6 μm. X-ray diffraction analysis shows that CuAl2 and Al4C3 are synthesized in all considered treatment regimes, and the quantity of these phases depend on the specific treatment energy.
    The use of “three point – plane” electrode system instead of “point – plane” during HVED treatment of 87,5 % Al + 12,5 % Cu powder system in ethanol leads to the increase of quantity of synthesized Al4C3 and CuAl2 phases with the slight decrease in the dispersion efficiency.
    Up to 35% of particles in powder mixture, treated by HVED in ethanol with the use of “three point – plane” electrode system, have diameter close to the diameter of the initial powder mixture.
    It is shown that the preparation of powders with an initial composition of 87.5% Al + 12.5% Cu using HVED treatment in kerosene or ethanol with subsequent consolidation by SPS method allows obtaining metal-matrix composites of the Al – Cu – C system with increased indicators of hardness, electrical conductivity and wear resistance.

  • MATERIALS

    State and prospects of application of plastically deformed nanostructured metals, alloys, and sprayed coatings

    Machines. Technologies. Materials., Vol. 15 (2021), Issue 7, pg(s) 279-282

    It is shown that thermal stabilization of the polygonization substructure up to 60 min is provided by a combination of uniaxial compressive deformations, namely dynamic by 30% and static by 30%, followed by pre-recrystallization heat treatment (PHT) at the initial recrystallization temperature. This ensures subgrain size of 80… 187 nm, while strength characteristics increase by 10… 30% with sufficient ductility.
    It is shown that PHT provides the formation of nanoscale elements in electric arc coatings with Sv-08G2S (Св-08Г2С), and additional deformation of the coating allows to increase the thermal stability of the polygonization substructure up to 40… 50 min. It is found that the combined deformation and subsequent PHT of steels provides an increase in the calculated number of nanoscale subgrains from 15 to 65%.

  • MATERIALS

    The impact of high voltage electric discharge treatment on the properties of Cu – Al powder mixture

    Machines. Technologies. Materials., Vol. 15 (2021), Issue 6, pg(s) 248-251

    Studies of the impact of high voltage electric discharge (HVED) treatment on the dispersion and phase composition of 87,5 % Al + 12,5 % Cu powder system were performed. It was shown that HVED treatment in kerosene with specific treatment energy of 5 MJ/kg leads to the decrease of mean diameter of treated powder from 15 to 13 μm, and the increase of specific treatment energy leads to the decrease of mean diameter of treated powder from 15 to 6 μm. X-ray diffraction analysis shows that CuAl2 and Al4C3 are synthesized in all considered treatment regimes.
    HVED treatment with increased specific treatment energy leads to the increase of quantity of synthesized Al4C3 phase. The use of “three point – plane” electrode system instead of “point – plane” during HVED treatment of 87,5 % Al + 12,5 % Cu powder system leads to the increase of quantity of synthesized Al4C3 and CuAl2 phases, while the efficiency of powders dispersion slightly decreases. Up to 40% of particles in powder mixture, treated by HVED in kerosene with the use of “three point – plane” electrode system, have diameter close to the diameter of the initial powder mixture