Influence of various types of treatment on the structure, density, and electrical conductivity of deformed alloys of the Al–Mg system

Resumo

A comparative investigation on the influence of AlZr4, AlZr10, and AlSc2 modifying master alloys, as well as magnetic-pulsed treatment (MPT) on density (in the liquid and solid states), electrical conductivity (in a solid state), and macrostructure of AMg5 and AMg6 alloys is performed. Mater melts are poured into special facilities providing cooling rates during the crystallization of ~10², ~10³, and ~10⁶C/s. Master alloys are introduced into the melts in an amount of 0.01% by the modifier element. It is shown that the modifying treatment of the melts by additives of nucleating master alloys promotes an increase in alloy densities in liquid and solid states. The electrical conductivity of alloys with additives of AlZr4 and AlZr10 master alloys lowers. The introduction of the AlSc2 master alloy increases in electrical conductivity of AMg5 and AMg6 alloys. This effect is established for the first time and requires additional investigations. It is established that, when compared with AlZr4 and AlZr10 master alloys, the AlSc2 master alloy prepared by crystallization in a water-cooled roll crystallizer most strongly affects the physical properties of alloys. It also provides the maximal macrograin refinement. MPT of alloys according to the axial effect scheme, similarly to the introduction of modifying master alloys, promotes an increase in the density of alloys in liquid and solid states. Electrical conductivity increases after MPT like after the addition of the AlSc2 master alloy into the melts. Alloy macrograin refining during MPT is comparable with the modification with the AlZr4 master alloy. Based on comparative investigations, it is concluded that MPT can be attributed to physical modification methods. It is proposed to use the determination procedures of density and electrical conductivity for the express evaluation of the modifying efficiency of studied effects.