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Field Effects for Processing of Ultralightweight Materials with Superior Properties


OBJECTIVE: Demonstrate the application of electromagnetic fields to develop, manipulate, process, and produce ultralightweight metals with superior properties. DESCRIPTION: The Army is highly interested in the application of electromagnetic fields for development of ultralightweight metals with tailored microstructures and properties. The current methods used to manipulate metal properties involve varying scale, composition, temperature, and pressure to improve strength, hardness, facture toughness, elastic modulus, density, etc., but the use of these traditional techniques for tailoring a wide range of chemical and physical properties is reaching a plateau. It is worth noting that significant ongoing research is being dedicated to re-engineering and exploring the creation of materials at the nanoscale, which holds potential for future applications that inherently hinge on surmounting scalability, assembly, and producibility challenges. However, there is an emerging technology that goes beyond factors of scale, composition, temperature, and pressure, and holds great promise in facilitating the realization of transformal materials with the aid of externally applied fields. The application of fields may alter phase transformation pathways, create new microstructures, shift equilibrium favoring new metastable alloys, align phases, manipulate and shape nanoscale architectures, and produce materials with revolutionary structural and multifunctional properties otherwise unattainable by conventional processing and production methods. The application of electromagnetic fields offers the unique opportunity to direct the architecture of materials features across atomic, molecular, micro, meso, and continuum levels. These fields may either be used to induce a permanent material property improvement or to selectively activate enhanced time-dependent properties via dynamic stimulation. Relatively low energy field-assisted processing methods such as spark plasma sintering (SPS), microwave sintering, and flash sintering have been developed to introduce electric and microwave fields for reduction of sintering temperatures and times [1-3]. Ultrahigh electric and magnetic fields have been applied during material consolidation to enhance material properties and alter conventional phase diagrams, pushing the limits of traditional materials science [4]. However, the fundamental thermodynamics and reaction kinetics that result in improved processing and revolutionary changes in properties are not well understood. Research on materials subjected to ultrahigh magnetic fields has been conducted at the National High Magnetic Field Laboratory (NHMFL) [5-6]. As an example, work by Oak Ridge National Laboratory (Ludtka et al) at the NHMFL has led to prediction of modified phase diagrams for a number of metals, including bainitic steel under a 30T applied magnetic field [4]. While several field-assisted methods have recently emerged, the goal of this effort is the development of new technologies that combine, augment, or control metal properties with electromagnetic fields and concurrently drive dynamical processes within assembly and production. The overarching technical challenges are to (1) develop a fundamental understanding of the chemical, physical, structural, and engineering aspects of field augmentation of metals, (2) identify phenomena that enable control of applied field manipulation of metals (3) develop concepts and approaches demonstrating enhancement to strength, hardness, facture toughness, elastic modulus, etc., (4) perform numerical modeling to describe and predict electromagnetic field influence on properties, (5) elucidate approaches that enable field control for scale-up of metals production, and (6) develop an agile manufacturing design for in-house fabrication and commercial licensing. PHASE I: Perform research and analysis that will allow for the demonstration of new concepts to apply electromagnetic fields (electric, magnetic, microwave, etc.) for the development of high specific strength metals with tailored microstructures and properties. Concepts should demonstrate a significant enhancement in strength, hardness, fracture toughness, elastic properties, etc., for metals and metal alloys (e.g. magnesium, aluminum, etc.). Concept evaluation will include fabrication of coupons that demonstrate significant property improvements when compared to current state-of-the-art metals via comprehensive characterization techniques (microscopy, property testing, nondestructive evaluation, etc.). Explore the incorporation of derived principles and theories into modeling and simulation tools with design predictive capabilities. PHASE II: Demonstrate an approach that enables field control for scale-up of metals production through the development of a novel process and a functional system for applying electromagnetic fields. Design and construct the necessary equipment and devices for accurately and reproducibly applying electromagnetic fields to fabricate metals with improved properties. Continued investigation and insight into the physics of the interactions between the applied fields and metals is also required as it relates to scale-up. Development of appropriate process models is necessary and required. In-situ characterization capabilities including process control and feedback are desired but not required. PHASE III: Develop an agile manufacturing system for in-house fabrication and commercial licensing by assembling commercial equipment suitable for applying electromagnetic fields of interest to a range of metals during processing under necessary temperature and pressure conditions. This system will include in-situ characterization capabilities and process control for quantitatively analyzing the effects of electromagnetic fields in real-time (microscopy, x-ray diffraction, nondestructive evaluation, etc.). Demonstration of this innovative system for fabricating metals with tailored and enhanced properties will assist the proposer in commercialization of the process or metals developed under this effort. Anticipated commercial applications may include novel advanced metals, electromagnetic equipment and devices, and modeling tools that accurately simulate the effects of applied electromagnetic fields on materials processing. The potential advantages of developing these applications include energy savings, property control and tailoring, and small volume production, which are equally valuable to both commercial and defense manufacture. Virtually all metals and some other materials industries, even commodity industries, as well as commercial and defense aerospace, automotive, and ship industries could benefit.
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