First-principles study of physical properties of L12-Al3X structural phases for heat-resistant aluminum conductors
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. State Key Laboratory on Lightweight High-strength Structural Material, Central South University, Changsha 410083, China;
3. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China)
2. State Key Laboratory on Lightweight High-strength Structural Material, Central South University, Changsha 410083, China;
3. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China)
Abstract: 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.
Key words: aluminum conductor; L12-Al3X structural phase; first-principles; mechanical properties; thermodynamic properties; electrical conductivity; valence bonds