Abstract: A metallic glass fastening screw that is not susceptible to loosening, and is capable of implementing fastening with high strength and reliability. In processing a screw thread and a screw groove of a screw, amorphous bulk metallic glass is form-rolled at glass transition temperature or less of the bulk metallic glass serving as a member to be processed. The bulk metallic glass has a plastic strain property introduced by plastic working such as form rolling, to improve ductility. A relationship of d>0.022×D is set so that a depth from a bottom of the screw groove in the region where the plastic strain is introduced is d and an outside diameter of the screw is D, to relax stress concentration of tensile stress generated in a region at the bottom of the screw groove due to tension (axial force) applied to the screw in fastening.

Abstract: Provided are a method of molding an amorphous alloy, which has a high degree of work freedom regardless of components of an amorphous alloy, in particular, metallic glass and of the shape of an article to be molded, and is capable of producing a molded article having less pores, and a molded object produced by the molding method. The method of molding an amorphous alloy includes: a melting step of melting an amorphous alloy; a differential-pressure casting step of injecting a melt of the amorphous alloy into a casting mold positioned below the melt and evacuating the casting mold; and a processing step of processing the melt by heating and pressurizing the melt in the casting mold while keeping the melt in a supercooled state.

Abstract: [Problem] To prepare an amorphous alloy as an authentic industrial-use material with a wide range of applications by solving various problems such as delayed fracture and ductility. [Solution] The alloy includes 63 at % or more of Ni and consists only of, as a semimetal for amorphization, other than P. The semimetal may include, for example, 10 to 25 at % of B and one or more of Cr, Mo, and Nb as remaining main elements.

Abstract: A metallic glass fastening screw that is not susceptible to loosening, and is capable of implementing fastening with high strength and reliability. In processing a screw thread and a screw groove of a screw, amorphous bulk metallic glass is form-rolled at glass transition temperature or less of the bulk metallic glass serving as a member to be processed. The bulk metallic glass has a plastic strain property introduced by plastic working such as form rolling, to improve ductility. A relationship of d>0.022×D is set so that a depth from a bottom of the screw groove in the region where the plastic strain is introduced is d and an outside diameter of the screw is D, to relax stress concentration of tensile stress generated in a region at the bottom of the screw groove due to tension (axial force) applied to the screw in fastening.

Abstract: A metal-made high-precision gear and a gear mechanism are disclosed. The precision gear is made of a novel material which does not exist in conventional materials for precision gears, including resins and tool steels, has high hardness, strength and excellent surface smoothness, and is superior in workability. In the precision gear which is formed of an amorphous metal alloy having a ternary, quaternary or higher composition containing iron group elements, such as Fe, Co, Ni, and Cu, Ti, Zr, Hf, as the principal elements, the precision gear whose module is 0.2 or less is made of the amorphous metal alloy having a disordered structure which does not have a fixed regularity and whose XRD pattern is a halo pattern, namely exhibits a broad peak.