The stability of structures with icosahedral local order in Al-based alloys with transition metals

The paper considers the stability of the phases formed in alloys of aluminum with transition metals (TM) in terms of the theory of coordination compounds. The structural stability is related to the degree of distortion of the first-neighbor coordination icosahedra commonly found around TM atoms. Changes in the symmetry of coordination polyhedrons are explained in terms of the Jahn–Teller theorem. The stability of the structures may be correlated with the effective charge of the TM atom and with the electronegativity of its neighbors: the phase transforms to the structure with lower symmetry when the electronegativity or effective charge decrease.