Towards the growth of single quasicrystalline grains in Al-Cu-(Fe, Cr) alloys after mechanical alloying and subsequent high temperature heating

Coarse grains growth in Al65Cu23Fe12 and Al73Cu11Cr16 mechanically alloyed powders was studied. Heating up to 950 °C and further rapid cooling produces a range of single quasicrystalline grains having different sizes, shapes and the degree of perfection. In the Al-Cu-Fe system both secondary recrystallization in the solid state and crystallization from liquid state were found. Contrary to the mechanism of nucleation in the liquid state and further growth of nuclei we demonstrate another mechanism – the ready nuclei which survived after the short heating are incorporating the molten material, which results in the formation of perfectly shaped single grains. In the Al-Cu-Cr system only secondary recrystallization in the solid state and no crystallization from liquid state were found. [Display omitted] •Secondary recrystallization at heating forms complex quasicrystalline agglomerates.•New mechanism of single quasicrystals growth was discovered in Al-Cu-Fe system.•Perfect Al-Cu-Fe single quasicrystals grow from melt on the solid substrate.•Perfect Al-Cu-Cr single quasicrystals grow through secondary recrystallization.