Single crystal growth of Al13Co4 and Al13Fe4 from Al-rich solutions by the Czochralski method
Crystal Research and Technology 43(11): 1161-1167
Czochralski growth of large metallic alloy single crystals of Al13Co4 and Al13Fe4 from Al-rich solutions has been demonstrated for the first time. A detailed description of all decisive steps of the growth procedure is given with particular emphasis to seeding from a native phase as well as spontaneous nucleation if no seed crystal from a preceding experiment is available. Czochralski growth in a high-temperature solution system requires much lower pulling rates compared to typical growth experiments from the melt and a time-dependent temperature program to compensate the change of the liquidus temperature that results from the permanently increasing Al content of the liquid phase. With a given amount of the initial melt, the size of the Al13Co4 crystals is limited by the rather narrow temperature range of the Al13Co4 primary crystallization window, followed by Al9Co2 phase crystallization. In the Al-Fe system, despite the huge temperature range of equilibrium between Al13Fe4 and its Al-rich melt, Czochralski growth of Al13Fe4 is restricted to higher temperatures due to the limited solubility that leads to mother liquid inclusions even at extremely low pulling rates.