Crystal structure and phase stability of AlSc in the near-equiatomic Al–Sc alloy

Abstract Intermetallic compound AlSc is found in the equiatomic Al–Sc binary alloy. The present work indicates that the orthorhombic AlSc with the Au 2 CuZn-type structure can be formed at 50 at.% Sc, while the CsCl-type (B2) AlSc will be formed at 55 at.% Sc. After annealing at 1100 °C, some orthorhombic AlSc grains transit to the B2 structure, and the annealing at lower temperatures leads to the disappearance of B2 phase, indicating that the B2 AlSc is also a metastable phase in the alloy at lower Sc content (