Understanding Czochralski growth of decagonal AlCoCu
Philosophical Magazine 86(3-5): 323-328
Czochralski growth of decagonal AlCoCu was investigated using spontaneous nucleation as well as AlCoNi seeds of different orientations. Contrary to all knowledge gained from the growth of large single crystals in the Al-Co-Ni system, growth of AlCoCu quasicrystals proved to be much more complicated. Second-phase inclusions were found to be the main problem, resulting in various features affecting regular crystal growth. Even at extremely low pulling rates, this could only be solved by growing along the two-fold -direction. Finally, large-grain Al67.5Co20.0Cu12.3 single crystals, having a rather homogeneous elemental distribution, were successfully grown from the initial melt of composition Al66Co10Cu24.