The mechanical, thermodynamic properties and electrical conductivities of L1₂-Al₃X (X=Zr, Sc, Er, Yb, Hf) structural phases in aluminum conductors were investigated through a first-principles study. The results demonstrate that all structural phases have good alloy-forming ability and structural stability, where Al₃Zr is the most superior. Al₃Zr, Al₃Hf and Al₃Sc have enhanced shear and deformation resistance in comparison to other phases. Within the temperature range of 200-600 K, Al₃Er and Al₃Yb possess the greatest thermodynamic stability, followed by Al₃Hf, Al₃Zr and Al₃Sc. Al₃Er and Al₃Yb have higher thermodynamic stability than Al₃Hf, Al₃Zr and Al₃Sc. All structural phases exhibit substantial metallic properties, indicating their good electrical conductivity. The electrical conductivities of Al₃Hf and Al₃Zr are higher than those of Al₃Er, Al₃Yb and Al₃Sc. The covalent bond properties in Al₃Sc, Al₃Er and Al₃Yb enhance the hardness, brittleness and thermodynamic stability of the structural phase. The thermodynamic stability of Al₃Sc is significantly reduced by ionic bonds.