Manipulating Nanostructure During High-Speed Casting of Glassy Metals

点击翻译按钮获取中文摘要

During processing, most metals such as iron or aluminum will solidify into an ordered atomic-scale crystalline structure. In contrast, if sufficiently hindered during the final stages of processing, solidified metals will lack atomic-scale order. In this study, a planar-flow casting process is used to produce a disordered structure known as glassy metal. Glassy metals often have favorable properties such as ultra-high strength for a glassy stainless steel. The favorable electromagnetic properties of the alloys under study are that they enable energy-savings in applications such as electric vehicle power systems, power harvesting from wind or photovoltaic sun farms and power distribution. Such properties can be further enhanced by incorporating fine features, or nanostructure. This study proposes a new approach to incorporating these fine features during planar flow casting. To be able to manufacture green-enabling products using a technique that itself has low carbon footprint represents a double benefit to society. As part of this project, community outreach will foster the interest of school children in science, technology, engineering and mathematics with a special focus aimed at encouraging high-school girls toward technical careers.The goal is to advance the ability to rapidly solidify thin metallic glass alloys continuously at speeds of meters per second, all while controlling in real-time the formation of nanocrystals. Control is sought of the extent to which crystallization occurs and where in the solidified product it occurs. At production speeds of meters per second, this represents unprecedented nanostructure control. The intellectual significance of this work relates to the non-equilibrium materials science of rapid transformations on the atomic scale in the presence of high thermal gradients. The approach will include experiments using a modified planar-flow casting machine, characterization of the product structure using X-ray diffraction and transmission electron microscopy, simulation of the temperature field within the material and substrate, and mathematical modeling of the metal-on-metal contacting event. The results of this effort will have impact on high speed non-equilibrium processing for materials other than metals as well.