Design of multicomponent aluminium alloy containing 2 wt% Ca and 0.1 wt% Sc for cast products

A qualitative and quantitative analysis of the new Al-Ca-Mn-Fe phase diagram in the region of the aluminium corner is carried out using both thermodynamic calculations and experimental methods. Using the obtained data, the principal possibility of creating cast sparingly alloyed aluminium alloys with calcium, manganese, scandium and zirconium at allowable iron contents of up to 0.4% that do not require solution treatment and quenching in water is justified. At the selected concentrations, the entire amount of manganese (1%) is practically included in the aluminium matrix, while calcium (∼2%) and iron are in the multiphase eutectic, which has a fine structure. The joint introduction of 0.25% Zr and 0.1% Sc into the alloy leads to precipitation hardening due to the formation of the L12-Al3(Zr,Sc) phase nanoparticles during annealing. Based on the experimental data for the model multicomponent Al2CaMnFeZrSc alloy, it is shown that the mechanical properties of the castings of such alloys, which were obtained in a permanent mould and then simply annealed, are comparable to the commercial 356.0 alloy, heat-treated according to the T6 regime.