Stoichiometry of Quasicrystalline Al–Mn

Abstract

Electron microscopy has shown that in rapidly solidified Al-(14–20) at.%Mn alloys a new metastable phase of a quasicrystalline phase with the icosahedral symmetry, which was first discovered by Shechtman et al. (Phys. Rev. Lett. 53 (1984) 1951), is formed but with a considerable amount of fcc Al second phase in alloys with lower Mn content. From the change with Mn content of the intensity of fcc Al lines in the powder X-ray diffraction spectrum, the stoichiometry of the Al–Mn quasicrystalline phase is concluded to be nearly Al₄Mn (∼20.5 at.%Mn), being at variance with the reported composition of Al₆Mn.