THE OBTAINING NANOPOWDER PSEUDO-LIGATURES CU-ALN FOR MODIFICATION OF ALUMINUM ALLOYS

Abstract

The article presents results of study of the mechanical mixing and subsequent compaction of powder mixture, consisting of powder - carrier electrolytic copper (Cu) with particle size of 20...100 microns with nanopowder composition, modifier, of powders aluminum nitride (AlN) - 65 % and sodium hexafluoroaluminate (Na3AlF6) - 35 % with particle size of 100 nm, obtained by azide technology of self-propagating high-temperature synthesis (SHS). The mixtures, containing 2.5...5 % (mass) of the modifier, were investigated. The preparation of investigated powder mixtures Cu-AlN was performed by mechanical mixing in planetary centrifugal mill «Pulverisette-5» and in mill «Drunken barrel» within 60 minutes with speed 150 rpm/min and 45 rpm/min respectively. The chemical composition of the obtained powder compositions was investigated. Analysis of initial mixing of powder components was conducted. Some physical and technological properties of the obtained powder mixtures: particle size distribution, density, flowability and bulk density, were determined. The formation of ligature briquettes - nanopowder pseudo-ligatures of composition Cu-AlN with different contents of dispersed modifier carried out by uniaxial cold pressing in cylindrical mold on hydraulic press PSU-50 with pressing pressure 19...23 MPa. The dependence of the porosity of the briquettes from the pressure of pressing is determined. Microstructures pseudo-ligatures pressed at minimum pressure of pressing are presented. Nanopowder pseudo-ligatures (compacts) 25 mm diameter, height to 2 mm, weighing 2.5 and 5 g, with relative density 58…87 %, intended for subsequent input in aluminum melt with the aim of modification are received.