Collaborative Research: Hybrid-Compatible Deformation Processing of Performance Critical Components

加法制造已成为制造复杂机械部件的可行途径，这些部件在航空航天、国防、汽车和能源领域有重要应用。不幸的是，通过加法制造的机器部件往往由于内部缺陷而不可靠。这禁止它们用于工业，因为有缺陷的部件可能以意想不到的方式响应正常的使用条件或过早失效。该奖项支持建立一种新的混合添加剂方法来制造无缺陷部件的研究，因此直接影响经济福利和国家安全。这种混合方法将使用局部严重变形来修复缺陷。支持这项研究的建模工作将使快速制造高质量的附加制造部件成为可能。该项目还将支持几项课堂教学举措，包括以K-12、本科生和研究生为重点的举措。这些措施包括(1)将研究成果纳入互动教育电脑游戏，以及(2)通过可在开放的社交媒体平台上观看的短视频脚本电影进行传播。该项目的目标是通过混合后处理方法促进对额外制造的部件的缺陷控制。为了实现这一目标，该方法将涉及在添加剂制造过程中在相互交织的步骤中系统地使用塑性变形，以减轻体积缺陷。建模工作将包括详细描述材料在分级塑性应变下的微观结构演变。感兴趣的微结构参数包括颗粒结构和缺陷结构。这些参数的变形响应将使用现场加载平台进行研究，该平台将与现有的电子显微镜和X射线计算机断层扫描仪一起工作。形变应变场将通过二次电子成像使用数字图像相关来表征。这些应变场将与演变中的微结构参数相关联，这些微结构参数将被同时表征。作为加工条件的函数，用于预测表面微结构的过程建模框架将被验证并用于确定后处理添加制造微结构的最佳混合策略。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Additive manufacturing has emerged as a viable route for fabricating complex machine components that have important applications in the aerospace, defense, automotive and energy sectors. Unfortunately, machine components made through additive manufacturing are often unreliable due to internal defects. This prohibits their industrial use as defective components can respond to normal service conditions in unexpected ways or fail prematurely. This award supports research to establish a novel hybrid-additive method for fabrication of defect-free components, and therefore directly impacts economic welfare and national security. This hybrid approach will repair defects using local severe deformation. Modeling efforts that will support this research will enable rapid fabrication of high quality additively manufactured components. The project will also support several classroom teaching initiatives including those focused at the K-12, undergraduate and graduate levels. These include (i) incorporation of research results into an interactive educational computer game and (ii) dissemination through short video-scribe movies available for viewing in open social media platforms. The goal of this project is to facilitate defect control in additively manufactured components through hybrid post-processing methods. For achieving this goal, the methodology will involve systematic use of plastic deformation in interwoven steps during additive manufacturing for mitigation of volumetric defects. Modeling efforts will involve detailed characterization of material microstructure evolution under graded plastic strain. Microstructure parameters of interest include grain structure and defect structure. The deformation response of these parameters will be studied using in situ loading platforms that will work with existing electron microscopes and X-Ray computed tomography machines. Deformation strain fields will be characterized using digital image correlation through secondary electron imaging. These strain fields will be correlated with the evolving micro-structure parameters that will be characterized simultaneously. A process modeling framework for prediction of the surface microstructure as a function of processing conditions will be validated and used to determine optimal hybrid strategies for post processing additively manufactured microstructures.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.