Development and Applications of Late Transition Metal Bulk Metallic Glasses

Bulk metallic glasses (BMGs) in metal-metal systems such as La

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, Mg

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, and Zr

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based alloys were first prepared in the early 1990s by the stabilization of supercooled liquid. Since then much effort has been devoted to the development of BMGs for both fundamental scientific research and for industrial applications. As a result, many unique and useful properties of BMGs have been found. In particular, research at the Institute for Materials Research has been concentrated primarily on early transition metal (Zr

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, Ti

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, and Hf

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based) systems, lanthanide metal (Ln

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based) systems, simple metal (Mg

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and Ca

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based) systems, and noble metal (Pd

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and Pt

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based) systems. Because of their excellent properties, BMGs are expected to emerge as a new type of industrial or engineering material. The development of late transition metal (LTM)-based BMGs is strongly encouraged due to material costs and the availability of raw material deposits. Therefore, an Fe-based BMG in the Fe–Al–Ga–P–C–B alloy system was successfully developed in 1995. Also at that time, three empirical component rules for the stabilization of a supercooled metallic liquid were proposed. These rules stated that (1) the multicomponent system should consist of three or more elements, (2) there should be a significant difference (greater than ~12%) in the atomic sizes of the main constituent elements, and (3) the elements should have negative heats of mixing. A variety of Fe-based, Co-based, Nibased, and Cu-based BMGs have been synthesized in accordance with these rules and other topological and chemical criteria. As a result, various unique properties of LTM-based BMGs have been obtained. These properties have not been obtained in any crystalline alloys. Therefore, it should be possible to extend the range of applications. This chapter reviews recent results on the formation, properties, thermal stability, workability, and applications of LTM-based BMGs.