SBIR Phase I: Continuous Fiber Ceramic Matrix Composite 3D Printing

这个小企业创新研究第一阶段项目将开发3D打印连续纤维增强陶瓷基复合材料（CMC）组件的工艺，用于涡轮机和内燃机、高超声速飞行器和卫星。CMC目前是一个25亿美元的市场，预计在未来十年内将增长两倍。利用3D打印生产CMC的能力将使当前应用中的上级设计成为可能，并使其能够用于更多的部件，这些部件目前受到Inconel和Invar等高温合金的较高密度和较低温度能力的限制。开发这种制造工艺将通过作为新CMC组合物的低成本测试平台来实现更多的基础材料研究，因为不需要模具并且周转时间更快。这也将使工程师能够以更快的设计周期开发更优化的系统。这种能力将导致涡轮机和内燃机的效率提高，从而大幅提高燃料效率，降低成本和环境影响。最后，3D打印CMC的能力将大大改善高温部件的几何复杂性，这将使下一代高超声速飞行器成为可能，支持国防。该项目的智力价值在于建立一种基于3D打印的CMC新制造工艺。熔融渗透是生产CMC的低成本方法，其从热解的聚合物基质复合材料开始，然后用熔融金属渗透。基体通常是酚醛热固性材料，但高温热塑性塑料最近已被证明适用于简单的试样。本项目将使用五轴连续纤维增强高温热塑性复合材料作为绿色坯体。由于热塑性塑料熔化，因此在热解步骤期间将使用支撑材料，这在保持部件几何形状方面是有效的。另外，将实施在热解之后而不是在形成聚合物复合材料之前在纤维上生长氮化硼界面层的新方法，因为在印刷期间的紧密拐角可能损坏界面层。最后，将尝试用较大弯曲半径的碳化硅纤维代替碳纤维进行3D打印。该项目将证明这种界面的有效性，提高了抗弯强度和韧性，并能够形成几何复杂的CMC，这是非常困难的，如果不是不可能的，使与其他方法。这两个里程碑将为开始为客户开发商业应用中的零件开辟道路。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Small Business Innovation Research Phase I project will develop the process to 3D print continuous fiber reinforced ceramic matrix composite (CMC) components for turbine and combustion engines, hypersonic vehicles, and satellites. CMCs are currently a $2.5b market that is expected to triple over the next decade. The ability to produce CMCs with 3D printing will enable superior designs in current applications, as well as enabling their use in a greater number of components that are currently limited by the higher density and lower temperature capabilities of superalloys such as Inconel and Invar. Developing this manufacturing process will enable more basic materials research by serving as a lower cost testbed for new CMC compositions since a mold is not required and turnaround times are much faster. This will also allow engineers to develop more optimized systems with a faster design cycle. This capability will result in efficiency increases in turbine and combustion engines for substantial improvements in fuel efficiency, reducing costs and environmental impact. Finally, the ability to 3D print CMCs will vastly improve geometric complexity of high temperature components, which will enable the next generation of hypersonic vehicles, supporting national defense.The intellectual merit of this project is in establishing a novel manufacturing process for CMCs based on 3D printing. Melt infiltration is a low cost method to produce CMCs, which starts with a polymer matrix composite that is pyrolyzed, and then infiltrated with a molten metal. The matrix is usually a phenolic thermoset, but high temperature thermoplastics have recently been proven viable for simple coupons. This project will use 5-axis continuous fiber reinforced high temperature thermoplastic composites as green bodies. Since thermoplastics melt, support materials will be implemented during the pyrolysis step, which are effective in retaining part geometry. Additionally, a novel process of growing a boron nitride interphase layer on the fibers after pyrolysis instead of prior to forming the polymer composite will be implemented since tight corners during printing might damage an interphase layer. Finally, 3D printing with larger bend radius silicon carbide fibers instead of carbon fibers will be attempted. This project will demonstrate the effectiveness of this interphase with improved flexural strength and toughness, and the ability to form geometrically complex CMCs that are extremely difficult, if not impossible, to make with other methods. These two milestones will enable a path to begin developing parts for customers in commercial applications.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.