Uniformity of the glassy state of iron-based metallic glassy particles and reproducibility of fabricating microparts

The uniformity of the glassy state of [(Fe_0.5Co_0.5)_0.75Si_0.05B_0.2]₉₆Nb₄ metallic glassy particles prepared using our own developed technique, called the pulsated orifice ejection method (POEM), was investigated. Differential scanning calorimetry (DSC) results revealed that the thermal histories of the particles prepared from the same batch were almost identical. This suggested that the particles with the same size/volume possessed almost the same glassy state and had advantages as raw materials for microparts. The fabricated final product using our proposed process, termed as micro viscous flow processing, where a single particle is compressed with a precise jig under strictly controlled processing conditions, was confirmed to maintain a fully amorphous structure. DSC scans of each micropart traced nearly the same path, which indicated that their glassy states were still almost identical after processing. The precise control of the temperature and applied load enable the final products to achieve almost the same thermal histories and also geometric shapes. This is the first report that proves the high reproducibility of fabricating Fe-based metallic glassy microparts with high quality. Our proposed sequential process may shed light on a new fabrication technique of microparts using metallic glasses.