Synthesis of Aluminum Alloys from Dispersed Waste Based on Aluminum

Abstract

This paper presents the results of research on the synthesis of aluminum alloys of the Al–Si–Mg (Ak7ch), Al–Si–Mn (AK12), Al–Si–Cu–Mg (AK6M2), and Al–Mg–Mn (AMg5) systems using dispersed waste: beverage cans (Al–Mn–Mg system), sawdust of a cast alloy (Al–Si–Mg system), and twisted chips of deformable alloys of the Al–Cu–Mg and Al–Mg–Mn systems. A study of the microstructure of waste in the initial state is performed and the typical sizes of the main phases are determined. The main criteria for the quality of recyclable waste are determined: the purity (kp), contact with the atmosphere (ka), and maximum recovery of metal (ММе). Based on the proposed criteria, the waste is graded according to recycling efficiency. The lowest total score is assigned to cans of waste. Sawdust from the AK9ch alloy had the highest score. Experiments on the synthesis of Al–Si–Mg (Ak7ch), Al–Si–Mn (AK12), Al–Si–Cu–Mg (AK6M2), and Al–Mg–Mn (AMg5) alloys have shown that the usable yield varies from 82 to 96%. The minimum yield of usable material is set for the AK12 alloy, whose charge composition is dominated by beverage-can waste. The chemical compositions of the alloys in terms of the content of the main alloying and impurity elements meets the requirements of regulatory documentations. Tests of mechanical properties have shown that the synthesized alloys have a guaranteed margin of strength and plasticity in comparison with the requirements of regulatory documentation. Based on metallographic studies, it is found that the microstructure of synthesized alloys does not contain nonmetallic inclusions and gas porosity. Unmodified and modified samples from the Al–Mg–Mn alloy (AMg5) are subjected to cold rolling in several passes until cracks form. On the sample from an unmodified alloy, cracks appear after the tenth pass. The modified alloy sample withstands 12 passes before cracking. The degree of deformation in the thickness of the sample from the unmodified alloy is 60.5%; for the modified one it is 67.2%.