2005 Volume 46 Issue 10 Pages 2291-2294
Ce-rich misch metal (Mm)-based bulk metallic glasses (Mm consists of Ce, La, Pr and Nd) with high glass-forming ability are developed in Mm–Co–Al alloy system. The critical diameter for glass-formation is 10, 5 and 3 mm, and the supercooled liquid region ΔTx (ΔTx=Tx–Tg, Tx is crystallization temperature and Tg is glass transition temperature) are 27, 90 and 79 K for Mm65Co25Al10 (Mm65), Mm60Co20Al20 (Mm60) and Mm55Co25Al20 (Mm55) alloys, respectively. Reduced glass transition temperature Trg (Trg=Tg⁄Tm, where Tm is melting temperature) is 0.62, 0.65 and 0.69 for Mm65, Mm60 and Mm55, respectively. The employment of the misch metal, which comprises multi-rare earth elements, instead of pure Ce in the Ce–Al–Co system can improve the glass-forming ability in spite of the tiny atomic size difference of the rare earth metals. The present alloy system is an exception to the criteria of ΔTx, Tg⁄Tm and different atomic size distribution as well as negative heat of mixing used for evaluating the relative GFA.