Fabrication of Fe- and Co-based metallic glasses and their high functional properties

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In this fiscal year Fe-base metallic glasses with the large supercooled liquid region before crystallization reaching 100K were found. The maximum diameter of the metallic glasses reaches as large as 5 mm. In addition, large supercooled liquid region of maximum 88 K was found in Co-base metallic glasses. This enable us to fabricate bulk shape specimens with a maximum thickness of 5 mm. Furthermore, rodshaped metallic glasses were prepared with a flux treatment for the Fe-based multicomponent metallic glasses. This preparation method enable us to prepare bulk metallic glasses with maximum thickness of 4 mm even in a low cooling rate. The flux treatment method is effective for decreasing coercivity and increasing supercooled liquid region by 30 %. The glass-forming ability, the stability of supercooled liquid region and the soft magnetic properties increase effectively applying the flux method, by which molten alloy is cleaned, for Fe-based metallic glasses in addition to Pd-based metall … More ic glasses. Based on the findings, ring-shaped bulk metallic glasses with good soft magnetic properties were prepared. Basis research for application is under promoting. The deformed Fe- and Co based metallic glasses, utilizing viscous flow deformation in the supercooled liquid region before crystallization, shows as good soft magnetic properties as metallic glasses prepared by low cooling rate. Bulk metallic glasses were succeeded in preparing by powder consolidation undegrading soft magnetic properties, The consolidation method is found to be appropriate for the fabrication of bulk metallic glasses. Fe based metallic glasses containing lanthanide metals as small as 3 to 4 atomic percent shows supercooled liquid region of 50 K.The small addition increase the glass-forming ability, resulted in fabricating bulk shaped metallic glasses with a several millimeters thickness. Furthermore, metallic glasses subjected appropriate annealing are found to have mixture structure of remaingn metallic glasse with nanometer sized crystalline phase and have good hard magnetic These results attracts attention as a new process to make new permanent magnet bulk materials. Less