Abstract:Self-designed Al8Si0.4Mg0.4Fe aluminium alloy was modified with Sr, followed by solid solution and aging treatments to regulate its microstructure and mechanical/electrical properties. The results show that after the modification treatment, the room-temperature tensile strength of the alloy remains nearly unchanged, the elongation at break slightly increases from 1.82% to 3.34%, and the electrical conductivity significantly increases from 40.1% international annealed copper standard (IACS) to 42.0% IACS. After the modification, the alloy was subjected to solid solution treatment at 515 ℃ for 8 h, followed by aging treatment at 180, 200, 220 and 240 ℃ for 6 h. With increasing aging temperature, the electrical conductivity increases monotonously from 41.4% IACS to 45.5% IACS, while the room-temperature tensile strength initially increases and then decreases. At 200 ℃, the alloy achieves an optimal balance between electrical conductivity and room-temperature tensile strength: the electrical conductivity is 42.5% IACS, and the room-temperature tensile strength is 282.9 MPa. When the aging temperature continues to rise, the alloy undergoes overaging. Although the conductivity continues to increase, the room-temperature tensile strength drops sharply, and it is only 177.1 MPa at 240 ℃.