Improving Electrical Conductivity of Commercially Pure Aluminium: The Synergistic Effect of AlB8 Master Alloy and Heat Treatment

This study aims to enhance the electrical conductivity of commercially pure aluminium by minimizing impurities and grain boundaries in its microstructure, ultimately improving the efficiency of electric motors constructed from rotors with squirrel cages made from this material. For this purpose, an aluminium–boron (AlB8) master alloy was added to aluminium with a purity of 99.7%, followed by the application of a grain-coarsening heat treatment to the rotors. To obtain commercially pure aluminium with boron additions of 0.05% and 0.1% by weight, specific amounts of the AlB8 master alloy were added into aluminium with a purity of 99.7%. Using these materials, squirrel cage components of rotors were produced via the high-pressure die-casting method. Subsequently, a grain-coarsening heat treatment of the rotors was performed at temperatures of 450 °C, 500 °C, and 550 °C, with holding times of 2, 6, and 10 h. The Box–Behnken design, which is based on statistical experimental design and response surface methodology, was employed to investigate the effects of adding boron and varying the heat treatment temperature and holding time on the electrical conductivity of commercially pure aluminium. The results showed that the synergistic effect of adding boron at 0.05 wt.% and applying the grain-coarsening heat treatment at a temperature of 550 °C for a holding time of 10 h significantly enhanced the electrical conductivity of commercially pure aluminium, increasing it from 60.62% IACS to 63.1% IACS. Correspondingly, the efficiency of the electric motor increased from 90.35% to 91.53%. These findings suggest that this hybrid method not only enhances the electrical conductivity of commercially pure aluminium but also has strong potential to improve its other properties, such as thermal conductivity. This will lead to products composed of components manufactured from the materials exhibiting better performance characteristics, such as increased efficiency and extended service life. Consequently, this innovative method will contribute economically and environmentally by facilitating the manufacture of high-performance products.