Abstract
Time-resolved in situ measurements using a combination of the electromagnetic levitation technique and energy dispersive diffraction of synchrotron radiation have been applied to the solidification of undercooled Al-Ni melts with 18–31.5 at.% Ni. Undercooling below the liquidus temperature did not alter the primary phase selection. However, during further cooling of semisolid samples the formation of a metastable decagonal quasicrystalline phase was observed, depending on the processing conditions. This metastable phase subsequently transforms and can only be retained at room temperatures when cooling with sufficient rates.