It is an alloy with high glass-forming ability (capable of φ14mm), high machinability, and high strength (with a compressive strength of over 4000 MPa).
Metallic glass alloys, unlike conventional crystalline metals, mostly do not exhibit plastic elongation in tensile tests. Even in compositions that do show plastic elongation, they only demonstrate about 2-3% elongation, resulting in very little ductility under uniaxial stress. Therefore, plastic processing such as rolling or forging, which is common with conventional crystalline metals, is difficult. Furthermore, metallic glass alloys have higher strength compared to regular metals, with some alloys reaching up to 5000 MPa, and their machinability is not as good as that of steel. However, metallic glass alloys have the characteristic that the viscosity of the material drops sharply above the glass transition temperature, allowing for various processing techniques (viscous flow processing) in the supercooled liquid region. By utilizing viscous flow, they can become materials with excellent machinability. This invention relates to Co-based metallic glass alloys that combine good machinability, high strength, and high glass-forming ability.