Local translational order in the NiTi2 icosahedral quasicrystal

Abstract

SUMMARYAfter heating to 400°C, the icosahedral quasicrystal in (Ti1‐IVI)2Ni alloys displays a kind of local or short range translational order as evidenced by a more or less commensurate arrangement of electron diffraction spots along one or several twofold directions. This is supported partly by a high resolution electron microscopic image which shows, in some parts of it, a somewhat regular arrangement of bright points. A structural model with some short‐range translation order in the range of a few nanometres along one of the fifteen twofold directions in the icosahedral matrix has been proposed and its optical diffraction pattern is in good agreement with the experimental observations.