Recent development and application products of bulk glassy alloys

Abstract

This paper reviews past developments and present understanding of the glass-forming ability, structure and physical, chemical, mechanical and magnetic properties of bulk glassy alloys (BGA) with the emphasis on recent results obtained since 1990, together with applications of BGA, achieved mainly in Tohoku University. After introducing the fundamental concepts around glassy alloys (GA) in Sections 1 and 2 describes the progress of the study of structural relaxation leading to the discovery of GA with a large supercooled liquid region. Section 3 reviews the history of BGA development, followed by BGA systems and their features in Section 4, and features of glassy structure in Section 5. Sections 6–9 summarize the engineering and standardization of Zr-based BGA, followed by the origins of the development of useful materials on the basis of experimental data on the compositional effect on the fundamental properties of basic ternary and quaternary Zr-based BGA. Sections 10 and 11 include the glass-forming ability and dynamic mechanical properties of Zr-based hypoeutectic BGA and Cu–Zr–Al–Ag BGA. Mechanical properties of Ni- and Zr-based BGA at low temperatures are shown in Section 12, while Section 13 describes the formation and properties of Ni-free Ti-based BGA. Sections 14 and 15 deal with porous Zr-based BGA, including spherical pores and commercialized ferromagnetic and high-strength Fe-based GA, respectively, then Section 16 reviews supercooled liquid formation. Applications for Zr-, Ti- and Fe-based GA are described in Section 17. In conclusion, Section 18 attempts to assess the present knowledge of the structure and physical properties and identify some outstanding problems for future work.