Elastic properties and phase stabilities of L1_2-A1_3 Sc precipitate phase in Al-Sc alloys have been topics of experimental and theoretical research over the past years. However, these properties of off-stoichiometric L1_2-A1_3 Sc have not been investigated. Firstly, in combination with Wagner-Schottky model, the first-principles total energy calculations based on density functional theory are performed to study point defect concentrations of intermetallic L1_2-A1_3 Sc each as a function of temperature and ...