Mossbauer spectroscopy study of Ti-Zr-Ni-Fe icosahedral and approximant phases

Quaternary Ti53Zr21Ni13Fe13 alloys were prepared by melt-spinning using per ipheral wheel speeds omega =19.5, 24.2 and 30m/s. The icosahedral (i-) phas e formation was studied using high resolution synchrotron radiation powder diffraction. An amorphous phase component is present irrespective of the ra pid solidification conditions, its volume fraction decreasing towards lower quenching speed values. The amorphous phase coexists with a b.c.c. rationa l approximant phase (W-phase). For omega below 20 m/s the formation of an i -phase was also noticed. Transmission Fe-57 Mossbauer spectroscopy measurem ents indicate that the number of asymmetrical Fe positions decreases with d ecreasing w in agreement with the improved structural perfection of the W-p hase and with the formation of an additional i-phase. (C) 2000 Elsevier Sci ence B.V. All rights reserved.