STTR Phase I: Rapid Investment Casting of Superalloys Using Microwave Technology

这个小型企业技术转移研究（STTR）第一阶段项目的更广泛的影响/商业潜力是通过展示一种新的快速和通用的熔模铸造系统来彻底改变金属铸造行业。该装置采用混合微波加热技术，可以直接照射铸造模具和金属熔体，从而降低能耗，并严格控制熔化/铸造过程。这种革命性的系统将允许任何规模的企业设计和制造小批量的金属零件，具有任何金属成分的复杂几何形状（从低温金属到高温高温合金）。通过将该技术与3D聚合物打印技术相结合来形成模芯，具有复杂几何形状的近净成形部件可以在几天内从计算机设计到铸造部件（与传统熔模铸造典型的几周交付相比）。这些属性解决了现代商业市场的许多当前需求，这些需求要求新产品以更短的产品开发时间快速周转。此外，美国先进制造业的未来将依赖于小企业以小批量、高价值和高质量的零部件来应对市场。该项目的智力价值将基于对一种炉体设计的研究，该炉体设计将利用微波能量快速熔化高温金属合金，用于熔模铸造过程中复杂零件的铸造。调查还将侧重于熔模铸造过程中的早期热步骤，以减少加工时间和能源消耗，从而节省成本和排放。微波加热已被证明用于各种食品和无机粉末，但很少或没有关于使用微波能量熔化和铸造金属的报道，特别是高温合金，如Ni和ti基合金。本文将对这种新型熔融技术进行研究。这项工作将展示微波耦合方法、过热水平和混合淬火技术（通过在熔模内选择性微波耦合）对所得金属零件的微观结构和机械性能之间的关系。这些信息将导致最终基于微波的金属熔炼机/铸造机的设计，这将为企业（从小型机械车间到大型铸造厂）提供在同一单元内快速铸造各种复杂形状，低和高温合金的能力。

The broader impact/commercial potential of this Small Business Technology Transfer Research (STTR) Phase I project is aligned with revolutionizing the metal casting industry by demonstrating a novel rapid and versatile investment casting system. This all inclusive unit is based on a hybrid microwave heating technology which permits direct irradiation of the casting mold and metal melt, which results in low energy consumption and tight control of the melting/casting processes. This revolutionary system will permit any size business to design and fabricate low volume metal parts, with complex geometries of any metal composition (from low-temperature metals to high-temperature superalloys). By coupling this technology with 3D polymer printing technology to form the mold core, near-net shaped parts with complex geometries may go from computer design to a casted part in a matter of a few days (compared to the typical multi-week delivery for traditional investment casting). These attributes address many of the current needs of the modern commercial market, which requires rapid turnaround of new products with shorter product development time. In addition, the future of advanced manufacturing in the US will be dependent upon small businesses responding to the market with small quantity, but high-value and high-quality parts. The intellectual merit of this project will be based on the investigation of a furnace design which will utilize microwave energy to rapidly melt high-temperature metal alloys for the casting of complex parts within an investment casting process. The investigation will also focus on early thermal steps within the investment casting process, in order to reduce processing time and energy consumption, and thus lead to a savings in cost and emissions. Microwave heating has been demonstrated for a variety of food products and inorganic powders, but there are little to no reports on the use of microwave energy to melt and cast metals, especially high-temperature alloys such as Ni- and Ti-based alloys. This work will investigate this novel melting technology. The work will show the relation between the method of microwave coupling, level of superheating, and hybrid quenching technique (through selective microwave coupling within the investment mold) on the microstructure and mechanical properties of the resultant metal parts. This information will lead to the design of a final microwave-based metal melter/caster, which will provide businesses (from small machine shops to larger foundries) the ability to rapidly cast a variety of complex-shaped, low- and high-temperature alloys in the same unit.