Fabrication and characterization of aluminum-based powders multi-reinforced with nano- and microparticles

Abstract

Multi-reinforced powders were obtained by high-energy ball milling in a planetary mill. The process of obtaining heterogeneous powders consisted of two stages. At the first stage, a nanocomposite powder of AlMg6 + 0.3 wt.% C60 was obtained. In the second stage, 10, 30, 50, and 70 wt.% Al2O3 were added to the obtained nanocomposite powder and processing continued. Methods such as scanning electron microscopy, X-ray diffraction, and particle size analysis were used to characterize the obtained powders. It is shown that after the first stage of processing, the particles of the composite powder are characterized by an irregular shape. C60 reinforcing particles in the form of nanosized agglomerates were fixed on the surface of aluminum powder particles. After the second stage of processing, the particle size of the powder mixture decreased from 17.8 to 12.3 μm, while the proportion of Al2O3 particles increased from 10% to 70% by weight. It is shown that the synthesized heterogeneous powders were a mechanical mixture consisting of complex composition agglomerates and micro-sized ceramic particles. Complex composition agglomerates were formed from nanocrystalline matrix material particles and C60, and also with Al2O3 microparticles embedded in them, as well as located on the surface. The concentration of Al2O3 particles on the surface and inside the agglomerates increased with increasing weight fraction of ceramic particles in the mixture. It has been found that the introduction of 10-70 wt. % Al2O3 into the powder mixture increases the microhardness of the powder particles by approximately 16-23%. The resulting multi-reinforced powder mixtures can be utilized for coating deposition using the cold gas dynamic spraying method.