Ce-rich misch metal-based bulk metallic glasses with high glass-forming ability

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 ΔT_x, (ΔT_x = T _x-T_g, T_x is crystallization temperature and T_g is glass transition temperature) are 27, 90 and 79 K for Mm ₆₅Co₂₅Al₁₀ (Mm65), Mm₆₀Co ₂₀Al₂₀ (Mm60) and Mm₅₅Co₂₅Al ₂₀ (Mm55) alloys, respectively. Reduced glass transition temperature T_rg (T_rg = T_g/T_m, where T _m 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 ΔT_x, T_g/T_m and different atomic size distribution as well as negative heat of mixing used for evaluating the relative GFA.