Metastable formation of decagonal quasicrystals during solidification of undercooled Al-Ni melts: In situ observations by synchrotron radiationO. Shuleshova1, D. Holland-Moritz2, W. Löser1, G. Reinhart3, G. N. Iles3 and B. Büchner1
1 Leibniz-Institut für Festkörper- und Werkstoffforschung (IFW) Dresden - 01171 Dresden, Germany, EU
2 Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR) 51170 Köln, Germany, EU
3 ESA External Research Fellows, ESRF/ILL - 38042 Grenoble, France, EU
received 26 February 2009; accepted in final form 8 April 2009; published May 2009
published online 12 May 2009
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.
64.60.My - Metastable phases.
61.44.Br - Quasicrystals.
61.05.cp - X-ray diffraction.
© EPLA 2009