Synthesis of aluminum alloys from aluminum-based dispersed waste

The paper presents the results of research on the synthesis of Al–Si–Mg (AK7ch), Al–Si–Mn (AK12), Al–Si–Cu–Mg (AK6M2) and Al–Mg–Mn (AMg5) aluminum alloys using dispersed waste: beverage cans (Al–Mn–Mg system), cast alloy sawdust (Al–Si–Mg system), twisted chips of Al–Cu–Mg and Al–Mg–Mn deformable alloys. The waste microstructure was studied in the initial state, and the typical sizes of main phases were determined. The main criteria for the quality of recyclable waste were determined: purity (k_p), contact with the atmosphere (k_a) and maximum metal recovery (М_Ме). Based on the proposed criteria, the waste was graded according to recycling efficiency. Can waste received the lowest total score, and AK9ch alloy sawdust 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 demonstrated that the yield varies from 82 to 96 %. The minimum yield was observed for the AK12 alloy with can waste predominating in the charge composition. The chemical compositions of alloys in terms of the content of the main alloying and impurity elements met the regulatory documentation requirements. Mechanical tests showed that synthesized alloys have a guaranteed margin of strength and plasticity in comparison with regulatory documentation requirements. Metallographic studies revealed that the microstructure of synthesized alloys is free from non-metallic inclusions and gas porosity. Non-modified and modified Al–Mg–Mn (AMg5) alloy samples were subjected to cold rolling in several passes until cracking. The non-modified alloy sample began to crack after the 10th pass. The modified alloy sample withstood 12 passes before cracking. The degree of deformation over the sample thickness was 60.5 % for the non-modified alloy, and 67.2 % for the modified alloy.

aluminum waste, recycling, alloy synthesis, yield, microstructure, mechanical properties

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