Influence of Heat Treatment on Recovery and Recrystallization Behavior of Cold Drawn Aluminum Wires

Abstract

This work investigates the influence of heat treatment on the recovery and recrystallisation behaviour of cold-drawn commercially pure aluminum wires, manufactured by the national cable enterprise EN.I.CA.B, Biskra. The wires were cold-drawn from an initial machine wire diameter of 9.5 mm to three final diameters: 5.92 mm, 4.24 mm, and 3.33 mm, corresponding to area reduction ratios of 61.17%, 80.08%, and 87.72%, respectively. Two annealing treatments were applied: a recovery annealing at 160°C for 90 minutes, and a recrystallisation annealing at 290°C for 60 minutes. The characterization techniques employed include tensile testing, Vickers microhardness measurements, and optical microscopy. The results indicate that recovery annealing induces a slight decrease in hardness through dislocation rearrangement and partial annihilation, without altering the grain structure. Recrystallisation annealing, on the other hand, leads to a significant reduction in mechanical strength and the formation of new strain-free equiaxed grains, resulting in a marked improvement in ductility.