Structural Stability, Mechanical, and Electronic Properties of AlTM (TM = Mo, Nb, Os, Re, Ru, Ta, Tc, Ti) Intermetallics.

Al-based intermetallic compounds possess excellent mechanical and thermal properties, making them promising candidates for high-temperature structural applications. In this study, the structural stability, mechanical properties, and electronic characteristics of AlTM (TM = Mo, Nb, Os, Re, Ru, Ta, Tc, Ti) intermetallic compounds were systematically investigated using first-principles calculations based on density functional theory. All alloys exhibit negative formation energy, indicating favorable thermodynamic stability. Elastic constant analysis shows that all compounds satisfy the Born stability criteria, confirming their mechanical stability. Among them, AlMo (205.9 GPa), AlNb (201.1 GPa), and AlTa (204.1 GPa) exhibit relatively high Young's moduli, while AlOs, AlRe, and AlRu demonstrate large bulk moduli and good ductility. The high Debye temperatures of AlMo (600.5 K) and AlNb (606.7 K) suggest excellent thermal stability at elevated temperatures. Electronic structure analysis reveals that all alloys exhibit metallic behavior with no band gap near the Fermi level. The hybridization between TM- and Al-3 orbitals enhances the covalent bonding between Al and TM atoms. This study provides theoretical guidance for the design and application of high-performance Al-based intermetallic compounds.