Hereditary influence of deformed waste on the efficiency of Al–Si–Mg and Al–Mg alloy modification

Abstract

   The paper provides the results of studies into the effect of the charge composition on the structure and mechanical properties of Al–Si–Mg (AK9ch) and Al–Mg (AMg6l) cast aluminum alloys. It was shown that deformed waste included in the charge composition (electrical waste of aluminum and waste of beverage cans based on the 3104 alloy – for AK9ch; AMg6 alloy plates – for AMg6l) contributes to the formation of dispersed micro- and macrostructure of working alloys in the solid state. The effect of modification (AlSr20 master alloy – for AK9ch; AlTi5 master alloy – for AMg6l) on the structure and mechanical properties of alloys obtained with various charge options was studied. Experiments on the effect of the charge composition on the AK9ch and AMg6l modifiability showed that the deformed waste structure is partially inherited by working alloys through the liquid state. With similar chemical compositions, alloys obtained with an increased proportion of deformed waste in the charge composition feature by smaller micro- and macrostructure sizes and improved mechanical properties (tensile strength and tensile elongation). It was found that when a certain amount of the modifier element (0.06 % Sr for the AK9ch alloy; 0.04 % Ti for the AMg6l alloy) is exceeded in these alloys, the over-modification effect appears. This is expressed in enlarged micro- and macrostructure parameters, as well as lowered tensile strength. The results obtained show that the optimal amount of the deformed waste proportion in the charge composition will make it possible to reduce the consumption of expensive modifying master alloys with a guaranteed effect of modification in practice.