Research On Continuous Fabrication Of Bulk Metallic Glasses And Behaviors Of Superplastic Deformation

Bulk metallic glass(BMG), also called Bulk Amorphous Alloys, Liquid metal, is a special alloy materials which have a structure of short-range order and long-range disordering and fabricated by modern casting methods of rapid quenching methods. ComPared with metallic materials with crystalline phase, BMG exhibit a much more excellent mechanical properties such as high strength, high hardness, high corrosion resistance and large elastic strain what make it to be a promising candidate in numerous application field of structure materials and function materials, and capture a lot attention of the scholar. But for the meanwhile, the fabricated method of BMG is still far away from mature, several drawbacks such as a exceedingly high cost and manufactured condition, poor efficiency, alloy of these factors constrict the development of commercialization and application of BMG. Our team independently developed a new preParative technology of horizontal continuous casting(HCC) of BMG. ComPared with the traditional metal preParative technologies, this technology are able to product the produce in continuous way which raise the efficiency and reduce the production cost. Therefore, in order to promote the commercialization of BMG, it’s rewarding and significant to further the study of continuous casting of BMG.This Paper aims at modification and bettering the technological Parameters of rod of Zr-based alloy fabricated by HCC fabrication method. By adjusting some technological Parameters of HCC, improve the microstructure and properties of the casting. Besides, the samples fabricated by different technological Parameters were comPared, and the effect of shifting the condition on the samples were estimated.BMG exhibit a quite high strength and hardness what make it impossible to cut and deform in low temperature, it is also difficult to grinding due to its excellent abrasive resistance. Consider to these characteristics of BMG, a processing method base on thermoplastic molding can be used as a replacement for the traditional metal processing technology. The principle is that the metal is heated to a temperature region of overcool in which the BMG would be soft and viscous fluid, that means it can be deformed under certain condition. Thus, how to carry out further deformation processing after the BMG samples were successfully fabricated was discussed in this Paper, and the application prospect in small devices was explored too.This selection of Zr-based alloy as research subjects due to its high glass-forming ability and thermal stability, the critical cooling rate of the Zr-based alloy is about 10 K/s, the supercooled liquid region width about 90 K. Meanwhile, the Zr-based bulk metallic glass also has excellent mechanical properties, the crashing strength close to 2 GPa and elastic limitation close to 2% which means a very great potential for development in structural or functional material field. Therefore, by using the alloy component of Zr55Cu30Ni5Al10, the effect of the change of the structure of composited graphite-water cooled copper mold and water flux on the structure and mechanical properties of the samples fabricated by HCC process was systemic studied. The results shows that change in structure of composited graphite-water cooled copper mold or cooling water flux would varied the structure and mechanical properties. In the same remaining of the rest Parameters, with the increase of graphite channel embedded composite mold depth from 5 mm to 40 mm, the microstructure and mechanical properties of Zr55Cu30Ni5Al10 alloy samples were changed. In the rest of constant Parameters, the microstructure and mechanical properties of Zr55Cu30Ni5Al1o alloy changed with the cooling water increased from 2 L/min to 8 L/min. Through the process optimization process in both aspects, after the optimum processing Parameters were achieved, the (Cu47Zr45Al8)96Y4 sample was prePared by this condition. After the microstructure analysis and mechanical properties testing, the sample remained mostly glass structure except a small number of Y2O3 Particles, room temperature compressive strength of 1.58GPa, Vickers hardness value is 532 Hv.The hot shear deformation test and compression deformation test were carried out with Zr55Cu30Ni5Al10 and (Cu47Zr45Al8)96Y4 sample, and the the stress-strain curve and the deformation results under different deformation conditions were comPared and analyzed.