International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The possibility of improving the structure and properties of aluminum cast alloy based on Al-Si-Mg due to the melt treatment in the magnetohydrodynamic installation has been studied in this work. Also, the optimization of the chemical composition and select the optimal modes of heat treatment of the alloys to improve the structure and complex of properties was carried out. It was shown that the most effective alloying element which improve the strength characteristics of Al-Si-Mg alloy is lithium. It was found that the introduction of lithium into the alloy in the amount of 0.2% leads to the modification of the Al-Si eutectic and provides the increase in the yield strength and tensile strength by 15%, while the ductility increases more than three times as much as compared to that of the base alloy.

Influence of small Sc, Ag, Zr, Ti, Mn addition on the stabilization of the structural state, the formation mechanisms and kinetics of the phase growth during the aging, and also technological casting properties in the industrial Al-Mg alloys were investigated. It has been established: maximum strengthening in these alloys is reached after the nature aging due to the precipitation of ordered Al3Mg phase that is isomorphic to the matrix. However, under prolonged nature aging the stable Al3Mg2 phase is precipitated in the matrix and on the grain boundary. It is accompanied by fall of the plasticity and decreasing the volume fraction of the strengthening Al3Mg phase. It is succeeded completely to prevent the formation of the stable phase under prolonged nature aging in the alloys quenched in the oi l and additional alloyed by Sc or Ag. Also Ag affects the cracking under the crystallization of alloys favorably. Using the complex of the Zr, Ti, Mn and Sc alloying elements increases the strength properties of the alloy at the quenched state slightly, but accelerates the formation of the stable phase during the nature aging.