PFI:AIR: - TT: Forming Metals Like Plastics: Thermoplastic Blowmolding of Metallic Glasses

Yale University, New Haven CT

Investigators

Abstract

This PFI: AIR Technology Translation project focuses on translating the ability to thermoplastically form metallic glasses like plastics to fill the need of net-shaping metals. Net-shaping, a process that shapes a material in one processing step into its final shape, is well established for thermoplastics, but thermoplastics are too weak for most structural applications. In structural applications that are critical, such as aerospace, automotive, and hard-tissue replacements, metals are typically used. Forming of metals, however, has been limited. This project will combine metal-like properties and plastic-like processing. Particularly, thermoplastic based blow-molding and stretch blow-molding, will be translated during this project from a scientific discovery into a technological process, which can meet the need for a metal net-shape process. These blow-molding processes have potentially vast commercial ramification as they could replace many of the currently used metal processing methods, and hence replace many of the applications currently occupied by metals and plastics. In order to reach such a translation, this project will determine processing parameters that are required for a commercial fabrication process. In addition, a commercial viability study will be carried out considering capital investment, processing time, and materials costs. As a product, a commercial apparatus and processing procedure will be determined in consultation with equipment manufacturers. Specifically, cycle time will be minimized, and processing conditions optimized for speed, energy efficiency, and robustness. Considering the redundancy of machining, joining, and other finishing procedures, and taking into account the processing speed and accuracy, blow-molding of metallic glasses is envisioned to replace currently used materials and processes used for electronic casings. This project addresses the following technology gap(s) as it translates from research discovery toward commercial application. The effect of high strain rate on the deformation behavior is not well understood. Particularly, if the metallic glass forming liquid remains to behave like a Newtonian liquid as strain rates exceeding 0.1/sec. Accurate understanding of the deformation behavior, the metallic glasses' response to temperature and pressure is crucial for future modeling of mold filling during blow-molding and stretch blow-molding. How the high strain rates effects the mechanical properties of the metallic glass also will be investigated. Bending experiments will be conducted and the strain to failure will be used as a quantitative measure for bending ductility. Involved personnel include graduate students, post-docs, undergraduate students, and visiting undergraduate students. They will be exposed to the whole range of technological development; from fundamental science of determining the deformation behavior, to engineering aspects of developing appropriate processes and machinery, to commercial and business aspects of viability and comparison studies. Students will be exposed to the state of the art metallurgy processes and characterization methods and will also develop a deeper understanding of the connection between science, innovation, and entrepreneurial skills.