Complex N-phase in the Al–Fe–Pt alloy system

New, so-called, N-phase revealed around ∼Al₇₉Fe₁₂Pt₉ (B. Grushko, J. Alloys Comp. 829 (2020) 154444) has been studied by 3D electron diffraction and high-angle annular dark-field imaging. Its structure is concluded to be monoclinic with the cell parameters of a ≈ 1.243 nm, b ≈ 1.654 nm, c ≈ 1.97 nm and β ≈ 107.24°. The symmetry of the unit cell can be described by either P2₁ (No. 4) or P2₁/m (No. 11) space groups. Despite extensive study, the structure solution of the N-phase was impeded by abundant structural defects. Electron diffraction data point to a close structural relation between the Al–Fe–Pt N-phase and the E-phases earlier observed in the Al–Ru–Rh or Al–Co–Rh(Ir) alloy systems. Both the N-phase and E-phases have very similar values of the b and c cell parameters while their cell parameters a are related as a_N ≈ a_E/[2sin(2π/5)]. The monoclinic Al–Fe–Pt N phase is established as a distinct member of the pseudo-decagonal intermetallic family.