Nanocomposites and nanomaterials
Formation of Composite Layers by Ultrasonic Impact Treatment of Cu–39Zn–1Pb Brass Using Silicon Carbide Reinforcing Particles
A. P. Burmak1, B. N. Mordyuk2,1, S. I. Sidorenko1, S. M. Voloshko1,
V. V. Mohylko1

1National Technical University of Ukraine ‘Igor Sikorsky Kyiv Polytechnic Institute’, 37 Peremohy Ave., UA-03056 Kyiv, Ukraine
2G. V. Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Blvd., UA-03142 Kyiv, Ukraine

The structure, phase composition and mechanical properties of composite coatings synthesized by ultrasonic impact treatment (UIT) of the surface layers of two-phase Cu–39Zn–1Pb brass with the addition of reinforcing SiC particles of different fractions, i.e. 3–5 μm, 14–20 μm, 40–50 μm, 80–100 μm, 160–200 μm, are studied. Owing to severe plastic deformation caused by UIT, there is a partial grinding and embodiment of the SiC powders into the near-surface layers of brass. The proposed approach allows synthesizing the high-strength composite coatings with a thickness of ∼ 50 μm.
The maximum hardening effect due to the maximum crystallites refinement of the phase components of brass is achieved under conditions of reinforcement with the SiC powder with a particle size of 160–200 μm. Application of the SiC powder fraction of 40–50 μm gives the best result in terms of the minimum of coherent-scattering regions size of the SiC powder and its higher volume fraction and more uniform distribution in the surface layer (EDX analysis shows minimum contents of Zn and Cu, and maximum contents of Si and C). Despite the fact that the microhardness of such a coating is slightly lower than those for the UIT-produced composites with the powders of larger size, the integrity, homogeneity, and uniformity of the formed composite coating are maximal in this case.