Growth of large single-grain quasicrystals in the Ag–In–Yb system by Bridgman method

Well-defined single-grain Ag–In–Yb icosahedral quasicrystals of order of centimeter have been grown by the Bridgman method. The scanning electron microscopy (SEM) observation showed that the compositional distribution in the single-grain quasicrystals is uniform and Laue X-ray diffraction measurements verified the formation of single-grain icosahedral quasicrystals. The natural growth direction of the single-grain quasicrystals is close to a direction parallel to a 2-fold axis. It turns out that the Yb content in the initial melt limited within 15–16 at.% is a critical factor determining the formation of single-grain quasicrystal. Based on the experimental result, the mechanism of the growth of single-grain quasicrystal and formation of intermediate zone between quasicrystal and approximant phases are discussed.