Effect of Cu and Heat Treatment on the Microstructure and Properties of 6101 Aluminum Alloy

The effects of Cu addition (0.01, 0.1, 0.5 and 1 wt.%) and heat treatment on the microstructure, electrical conductivity and mechanical properties of 6101 aluminum were investigated. Compared with alloys with lower Cu content, the appropriate addition of Cu is conducive to refinement of grains, thereby increasing the strength of 6101 aluminum alloy. When the Cu addition was increased from 0.01 to 1 wt.%, the hardness of the alloy increased by 10.3% and the tensile strength by 44.7%. However, the electrical conductivity of the alloy decreased with the addition of Cu. The alloys were rolled to further improve their properties. The rolled sheet of the alloy underwent solid solution treatment and aging strengthening, resulting in enhanced mechanical properties and electrical conductivity. The results showed that the conductivity of the alloys increased with the increase of the etching temperature and holding time, with an average increase of 5.8% for the four combinations of gold. In order to achieve a comprehensive match between the electrical conductivity and mechanical properties of the alloy material, the heat treatment process was selected with the addition of 0.5 wt.% Cu element, solid solution temperature of 545 °C with a holding time of 0.75 h, and aging temperature of 185 °C with a holding time of 8 h. By incorporating Cu and following this heat treatment process, the tensile strength of 6101 aluminum alloy sheet can reach 209.79 MPa, while maintaining an electrical conductivity above 53.5% IACS.