ERI: Making High-Temperature Alloyed Components by Combining Additive Manufacturing and Spark Plasma Sintering: Enabling Shape Complexity and Predicting Microstructures

该奖项全部或部分由2021年美国救援计划法案（Public Law 117 - 2）资助。放电等离子烧结是一种众所周知的制造技术，其中加压和快速加热同时应用，以实现颗粒到固体的固结，即使是高温金属，如钨合金，也具有低水平的缺陷。尽管对该技术有很大的兴趣，但是，它一直局限于简单形状的部件（即，呈圆柱形）。另一方面，尽管增材制造赋予了设计自由度，是制造复杂几何形状零件的理想选择，但高温合金的制造并没有取得可靠的成功。在该项目中，将采用增材制造（如粘合剂喷射）和放电等离子体烧结的组合来克服这些限制。所研究的技术集成代表了一种新的和有前途的方法，以高效和具有成本效益的方式生产由高温合金制成的复杂形状的部件，同时确保零件尺寸和微观结构的质量。此外，该项目还将探索研究场助烧结工艺基本原理的新可能性。此外，该项目还将促进少数民族本科生和研究生的教育、推广和保留，并通过与相关行业伙伴的合作，让高中生获得增材制造和火花等离子烧结等高端技术的实践经验，例如，加州纳米技术。该项目的总体目标是了解和开发放电等离子烧结技术的净成形能力，以生产复杂形状的零件，如螺旋锥齿轮，由难以使用传统或增材制造的材料系统制成。该项目将通过“可控界面”概念来应对这一挑战，该概念将增材制造能力与放电等离子烧结的全部固结潜力相结合，以生产复杂形状。可控界面由引入普通放电等离子烧结工具内的牺牲材料的三维打印的可变形体积表示。为了实现理想的可控界面设计，将对放电等离子烧结过程进行全面建模研究。这种组合技术中涉及的起始多孔组件的复杂性质需要扩展当前的粉末烧结建模框架，以更好地理解热和非烧结。放电等离子烧结中的热不平衡现象，以预测最终产品的微观结构和几何形状方面的最终加工结果。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的学术价值和更广泛的影响审查标准。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Spark plasma sintering is a well-known manufacturing technology, in which pressurizing and rapid heating are simultaneously applied to achieve particle-to-solid consolidation with a low level of defects even for high-temperature metals, such as tungsten alloys. Despite significant interest in this technology, it has been, however, limited to simple-shaped components (i.e., in cylindrical forms). On the other hand, though additive manufacturing has empowered the design freedom, ideal for making parts of sophisticated geometry, fabrications of high temperature alloys have not been reliably successful. In this project, a combination of additive manufacturing, such as binder jetting, and spark plasma sintering will be employed to overcome such limitations. The studied technology integration represents a novel and promising approach to produce complex-shaped components, made of high-temperature alloys, in an efficient and cost-effective manner, and yet, ensure the quality in part dimensions as well as microstructures. Moreover, the project will explore new possibilities for the investigation into the fundamentals of the field-assisted sintering processes. In addition, the project will contribute to the education, outreach and retaining of undergraduate and graduate students from minorities and to engaging high school students with hands-on experiences with high-end technologies such as additive manufacturing and spark plasma sintering via the collaboration with industry partners involved, e.g., California Nanotechnologies.The overall goal of this project is to understand and develop the net-shaping capability of the spark plasma sintering technology to produce complex-shaped parts, such as helical bevel gears, made of material systems difficult to be fabricated using either traditional or additive manufacturing. The project will address this challenge through the “controllable interface” concept, which combines the additive manufacturing capability to produce complex shapes with the full consolidation potential of the spark plasma sintering. The controllable interface is represented by a three-dimensionally printed deformable volume of a sacrificial material introduced inside common spark plasma sintering tooling. To achieve the desired design of the controllable interface, comprehensive modeling of the spark plasma sintering process will be researched. The intricate nature of the starting porous assembly involved in this combined technology requires extending the current powder sintering modeling framework to better understand thermal and non-thermal nonequilibrium phenomena in spark plasma sintering to predict the final processing outcomes in terms of the microstructure and geometry of end products.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.