Japan has developed a gold-copper-based metallic glass that can be bent and processed at low temperatures below 100°C

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The Institute of Metal Materials at Tohoku University in Japan has developed an Au-Cu-based metallic glass that can be processed by viscous flow at temperatures below 100°C. It has been proven that in relatively low-temperature regions such as boiling water, metal glasses in the shape of slender rods can be bent into a U-shaped form. Since the glass transition temperature (Tg) of this gold-copper-based metallic glass is as low as only 84°C, it can be shaped and processed in temperature ranges below 100°C. By enabling formative processing at lower temperatures than before, the research institute hopes it can be “applied in fields such as new types of nanomechanical components, biomaterials, and decorative materials.” Metallic glass refers to a material in which the supercooled region of the alloy’s liquid phase is wide, and it solidifies directly rather than crystallizing as the temperature drops. They generally share the following common characteristics: they are composed of multiple elements, three or more; the diameters of the atoms of these elements differ by more than 12%; and these elements tend to form compounds. When ordinary metals solidify, they typically form a crystalline structure in which the constituent atoms are arranged in an orderly manner. In contrast, metallic glasses do not have a crystalline structure; instead, their atoms are dispersed in a amorphous state during solidification. The supercooled liquid region (ΔTx) of the gold-copper-based metallic glass developed this time is as high as 35°C, granting it excellent metallic glass-forming capability. As a patent application is currently being prepared, the detailed composition of this glassy metal alloy has not been made public. The corrosion resistance of this gold-copper-based metallic glass is even superior to that of the representative stainless steel SUS316L (based on test results from immersion in 1N sulfuric acid solution), with its strength against failure exceeding 800 MPa. This is because its surface is amorphous, with no surface defects that could cause corrosion. This research and development is part of the collaborative project \"Joint Research on the Bonding of Metamaterials and Inorganic Materials\", a project carried out by national research institutes in Japan. It was developed jointly by three material research institutes: the Institute of Metal Materials at Tohoku University, the Institute of Applied Ceramics at Tokyo Institute of Technology, and the Institute of Bonding Science at Osaka University. This cooperation project was launched in 2005 and is set to last for 4 years, ending this year.