Stabilities, mechanical and thermodynamic properties of Al–RE intermetallics: A first-principles study

Abstract

Stabilities, mechanical and thermodynamic properties of 87 intermetallics in Al–RE binary system were studied by first-principles based on density functional theory (DFT). The results show that the calculated stabilities at T = 0 K are in good agreement with experimental values. Al2RE intermetallics exhibit the best stability in Al–RE binary compounds; and the stabilities in descending order are Al2RE, Al3RE, AlRE, Al11RE3, AlRE2 and AlRE3. The calculated Al–RE intermetallics possess mechanical stabilities. The hardness and strength of the most Al–RE intermetallics are greater than pure aluminum except AlCe, AlPr, AlEu and AlYb. The hardness and strength in descending order are Al11RE3, Al3RE, Al2RE and AlRE. Part of AlRE intermetallics exhibit ductility; the others are brittle. The heat capacities of Al–RE intermetallics in ascending order are Al–Sc, Al–Y, Al–lanthanides. On the contrary, the coefficient of thermal expansion (CTE) in ascending order is Al–lanthanides, Al–Y and Al–Sc.