Phase composition and mechanical properties of Al–1.5%Cu–1.5%Mn–0.35%Zr(Fe,Si) wire alloy

By using the experimental study and Thermo-Calc software simulation, the chemical composition of the model alloy containing 1.5% Cu, 1.5% Mn, 0.35% Zr (without the necessity of Sc addition) and with allowable Fe and Si content of up to 0.5% and 0.2%, respectively, have been justified. It was shown that the as-cast structure of the model alloy had the minimum quantity of eutectic inclusions of the Al₂Cu and Al₁₅(Fe,Mn)₃Si₂ phases formed during nonequilibrium solidification, whereas all zirconium content and about 1.1% Mn and 0.8% Cu were dissolved in the aluminium solid solution. Such structure provides high plasticity that allows for the deformation of ingots without their preliminary homogenization. By using the methods of radial-shear rolling (RSR), the 9 mm wire rods were produced from the ingot. The ductility of the rod was sufficient for cold deformation (rolling and drawing) with a high degree of deformation. In particular, a wire with diameters of 1 mm and 0.5 mm, and with UTS value of 430 MPa and 590 MPa, respectively, was obtained by cold drawing. Annealing after drawing reduces the strength properties and improves ductility of the obtained wire. EBSD analysis of the wire after annealing revealed that the described changes in mechanical properties are associated with the formation of a recrystallized grain structure (even in the presence of Zr and Mn-containing dispersoids in a large amount). Thus, using the example of the experimental model alloy, the principal possibility of obtaining a wire with a sufficiently high set of mechanical properties without the necessity of homogenization annealing, solution treatment, and water quenching has been shown.