The research of the processes of formation of porous non-ferrous metals

Abstract

Foamed metals are promising materials with a unique combination of mechanical and operational properties: low specific gravity, low thermal conductivity, ability to absorb acoustic and electromagnetic vibrations, and the ability to deform under a constant load. Currently, the most used methods for producing foamed aluminum and foamed magnesium are methods based on mixing gas or porophore into molten aluminum and forming a porous structure during the solidification of the aluminum melt. An alternative to this technology is the formation of a porous structure through the use of soluble granules that pre-fill the mold and after impregnating the granules with molten metal and solidifying the castings, they are leached. The work aims to determine the influence of casting modes and the size of granules on the depth of impregnation of granular filling with metal melt during the formation of porous aluminum castings. The authors proposed the technique for calculating the depth of impregnation of granular filling when producing castings of porous non-ferrous metals based on the calculation of melt cooling when moving along the thin-walled channel. The calculations made it possible to determine the depth of impregnation and establish the allowable wall thickness of the casting of porous aluminum, depending on the size of the granules used, the speed of the melt in a form, the mold temperature, and the temperature of molten aluminum. The study identified that to increase the depth of impregnation and obtain porous aluminum castings with thinner walls, it is advisable to increase the diameter of the salt granules and not the temperature and hydrodynamic modes of casting. The authors carried out calculations and identified the influence of the casting regimes and the diameter of the granules on the depth of mold impregnation to obtain porous castings from promising magnesium alloys.