First-principles study of physical properties of L12-Al3X structural phases for heat-resistant aluminum conductors
Yao-jie KONG, Hongying Li, Huijin Tao, W.C. Liu
Abstract
The mechanical, thermodynamic properties and electrical conductivities of L1 2 -Al 3 X (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 Al 3 Zr is the most superior. Al 3 Zr, Al 3 Hf and Al 3 Sc have enhanced shear and deformation resistance in comparison to other phases. Within the temperature range of 200−600 K, Al 3 Er and Al 3 Yb possess the greatest thermodynamic stability, followed by Al 3 Hf, Al 3 Zr and Al 3 Sc. Al 3 Er and Al 3 Yb have higher thermodynamic stability than Al 3 Hf, Al 3 Zr and Al 3 Sc. All structural phases exhibit substantial metallic properties, indicating their good electrical conductivity. The electrical conductivities of Al 3 Hf and Al 3 Zr are higher than those of Al 3 Er, Al 3 Yb and Al 3 Sc. The covalent bond properties in Al 3 Sc, Al 3 Er and Al 3 Yb enhance the hardness, brittleness and thermodynamic stability of the structural phase. The thermodynamic stability of Al 3 Sc is significantly reduced by ionic bonds.