Most popular Chinese Academy of Sciences successfu

2022-08-06
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Chinese Academy of Sciences successfully prepared micro and nano metal glass fibers

recently, Yi Jun, Wang Weihua research group of Institute of physics of Chinese Academy of Sciences/Beijing National Laboratory of condensed matter physics (Preparatory), and others developed a new process method to successfully prepare metal glass fibers. Relevant results were published in adv eng mater 12, 1117 (2010)

metal fiber and glass fiber not only play a very important role in engineering applications and people's daily life (such as glass fiber), but also cause extensive interest of scientists in the field of scientific research. Engineering metal materials have low preparation efficiency and high energy consumption because they do not have the ability of superplastic deformation. Because the glass has the ability of superplastic deformation in its supercooled liquid region, the glass fiber with smooth surface and uniform size can be prepared by high-efficiency and low-energy thermoplastic forming method. Like ordinary glass, metallic glass also has the ability of superplastic deformation in its supercooled liquid region. Whether we can use the thermoplastic method to prepare glass fiber to prepare metal glass fiber is a problem of concern. Scientists at home and abroad have made many attempts in this field, but they have never succeeded. The main reason is that the supercooled liquid region of metallic glass is not as wide as that of ordinary glass, and the change of viscosity with temperature is "technology-based", which is a management concept advocated and adhered to by covestro for a long time. The rate of conceptualization is very fast, and metallic glass is easy to be oxidized in the supercooled liquid region. Therefore, it is difficult to control the thermoplastic forming conditions for the preparation of glass fibers

Wang Weihua's research group pre applied a certain force to the metallic glass, and when the metallic glass was heated to the supercooled liquid phase, its viscosity would decrease. When the viscosity drops to the point that it can not bear the applied external force, the metal glass rod will undergo superplastic deformation to form metal glass fiber. This method can prepare a series of metal glass fibers of different micro and nano scale systems with high surface smoothness, uniform size and high roundness of cross section, which are very attractive to product developers. The obtained metal glass fiber size can be controlled from nano meter to micro meter, and the arithmetic mean value of 2 points can be taken, and the span scale range is 70 nm to hundreds of microns. Further performance research found that metal glass fiber not only has the excellent mechanical and functional properties of metal glass, but also overcomes the fatal disadvantage of metal glass brittleness, which limits its application. For example, metal glass fiber has good flexibility and can be woven. It can be predicted that metallic glass fiber will be widely used in micro nano electromechanical systems, composites, functional fabrics, sensors and other fields. In addition, when the size of metallic glass is smaller than these characteristic sizes, its physical behavior will be very different from that of macroscopic metallic glass. These micro nano metallic glass fibers with smooth surface, controllable size, uniform and high roundness cross-section are model materials for studying the mechanical properties, deformation mechanism and glass transition of metallic glass

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