Thermoplastic forming of bulk metallic glasses

Abstract

The viscosities of metallic glasses gradually drop with temperature rising in their supercooled liquid region (SLR) which enables them to be thermoplastically formed and totally overturns the processing method of traditional metallic materials: their forming can be realized under temperature and stress far below those of traditional metallic materials. Based on this property, metallic glasses are considered as the ideal miniature fabrication materials due to their unique amorphous structures and no crystalline defects such as dislocation and grain boundary.The thermoplastic micro forming of metallic glasses in their SLR is studied in the present paper. A universal equation which describes the filling kinetics of viscous metallic glasses in the non-circular channel is proposed with the help of fluidic mechanics, and the results may be theoretically useful for the micro application of metallic glasses.In addition, some applications in the micro thermoplastic forming of metallic glasses are introduced. A metallic glass mold insert for hot embossing of polymers is fabricated by the micro thermoplastic forming of metallic glass, and it is found to have many advantages in mechanical property, fabrication efficiency, surface quality, etc. compared with the traditional material and method. A similar approach is used to fabricate gratings, which may provide a new material and technology to produce gratings. The superhydrophobic metallic glass surface with excellent abrasion and corrosion resistance is also fabricated by constructing micro-nano hierarchical structures on metallic glass surface. The bulk metallic glass micro fuel cell is also finished and found to have good performance.