Growth of decagonal quasicrystal phase in laser resolidified Al72Ni12Co16

An ultra-high temperature gradient directional solidification process produ ced by a widened laser beam was adopted to achieve the directionally solidi fied microstructure of the stable decagonal quasicrystal phase in Al72Ni12C o16 alloy. X-ray, SEM, TEM and optical microscopy techniques were used to i nvestigate the microstructures and identify the phase. The directionally so lidified decagonal quasicrystal showed the facet morphology and grew in lat eral growth mode. The unusual periodic and quasiperiodic atomic structures of the decagonal quasicrystal and the epitaxial growth in the melt pool wer e considered to be the key factors influencing the growth morphology. The e xperimental results were consistent with the Toner's theoretical atomistic growth model.