ZN-MG-(Y, RE) QUASI-CRYSTALS - GROWTH EXPERIMENTS AND PHASE-DIAGRAMS

We report about our work on the preparation and characterization of ic osahedral Zn-Mg-(Y, RE) (RE = rare earth element) quasicrystals. We ob tained single grains of the icosahedral (i-) phase via slow cooling ex periments and with the Bridgman technique. We revealed a composition r ange of the i-phase, within which the structure changes. Additionally a systematic investigation of the Zn-Mg-Y phase diagram, including the determination of the primary solidification area of the icosahedral p hase is presented. It was found that for a growth from the melt a star ting composition with a low Y-content is needed.