Al–Ni–Ru icosahedral quasicrystal and coexisting decagonal quasicrystals with 0.4 nm periodicity, studied by atomic-resolution electron microscopy observations

Abstract As-cast and rapidly solidified alloys with compositions of Al 70− x Ni 25+ x Ru 5 ( x =0, 5, 10 and 15) and Al 70+ y Ni 20− y Ru 10 ( y =0 and 5) were examined by transmission electron microscopy. The results show that the Al–Ni–Ru icosahedral quasicrystal, which belongs to the F-type class, and the decagonal quasicrystal with a 0.4 nm periodicity can coexist in both the as-cast and rapidly solidified states. By means of high-resolution electron microscopy observations, the structural features of the as-cast Al–Ni–Ru icosahedral quasicrystal and the coexisting decagonal quasicrystal, with basic quasiperiodic order, were revealed.