CAREER: Understanding multiscale sintering kinetics and microstructural evolution in binder-based metal additive manufacturing

职业：了解基于粘合剂的金属增材制造中的多尺度烧结动力学和微观结构演变

• 批准号: 2237433
• 负责人: Jerard Gordon
• 金额: $ 65.75万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2027-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2237433&HistoricalAwards=false
• 关键词: CAREER; Understanding; multiscale; sintering; kinetics

NON-TECHNICAL SUMMARY: The process of using heat to turn powder into a porous solid without fully melting said powder is a manufacturing approach known as “solid-state sintering” (SSS). This technology forms the backbone of many important industrial processes for metal and ceramic materials such as powder metallurgy (P/M), metal injection molding (MIM), and field-assisted sintering (FAST). Overall, SSS platforms are advantageous because they do not require high temperatures to fully melt metal or ceramic powders which mean less energy is required to manufacture parts by sintering than by other standard processing methods. However, long-standing challenges still exist for sintering which include issues such as porosity, shrinkage and other changes in final shape that aren’t easily predicted due to events that occur at the scale of micro- and nanometers which aren’t well understood. This research project is revealing fundamental sintering mechanisms across multiple length scales by directly imaging powder surfaces and the internal structure of powders undergoing sintering in real-time using high powered x-ray experiments and high magnification electron microscopes. These state-of-the-art approaches are providing new knowledge on the way defects form and how internal structures change. Binder jet 3D printing (BJ3DP) is used as an example process since BJ3DP is of significant interest to the automotive industry but research findings contribute to new design strategies for a variety of SSS applications. This project also facilitates the training of undergraduate and graduate students in advanced manufacturing to address the current and growing skills gap in the U.S. This is being accomplished by exposing students to state-of-the-art characterization tools, engaging them in manufacturing research and involving them in professional development opportunities with industrial partners in the automotive industry. Additionally, this project is broadening participation through the recruitment and mentoring of graduate students hailing from underrepresented populations and hand-on community outreach events for students in grades K-12 in collaboration with the University of Michigan Museum of Natural History.TECHNICAL SUMMARY: Solid-state sintering (SSS) facilitates the efficient production of metal and ceramic materials, however, long-standing challenges remain due to a lack of fundamental insight of the dominant mechanisms facilitating internal microstructural development. Since the overall driving force for sintering (reduction of interfacial surface energy) can be facilitated by at least six different and potentially competing mechanisms, a robust understanding of SSS has been largely stymied by the absence of in-situ data. This research is employing novel in-situ x-ray computed tomography (XCT) and high energy diffraction microscopy (HEDM) to directly image 3D particle and internal microstructural evolution with micron-scale resolution during SSS in novel binder jet 3D printing (BJ3DP). Binder jet is used as an exemplar due to its strong potential for implementation in the automotive industry. Results are being combined with electron microscopy to understand the primary diffusion mechanisms at work during SSS, and how they are influenced by process, feedstock, and/or material factors. Findings are being used to test fundamental hypotheses on densification and grain-growth in BJ3DP and serve as calibration data for physics-based models. Overall, this new knowledge is enabling enhanced prediction of microstructure evolution applicable to a variety of SSS processes with strong industrial relevance such as powder metallurgy, metal injection molding, and field-assisted sintering. Integrated educational modules are being employed to reduce the currently growing manufacturing skills gap in the U.S. through research experiences for undergraduate and graduate students and professional development opportunities for students with the automotive industry. Educational and outreach activities include actively recruiting and training underrepresented minorities and women and providing accessible, hands-on activities for students in K-12 in collaboration with the U-M Natural History Museum to inspire interest in advanced manufacturing and STEM.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.

非技术摘要：使用热量将粉末变成多孔固体而无需完全熔化的粉末的过程是一种制造方法，称为“固态烧结”（SSS）。该技术构成了许多重要工业过程的骨干，用于金属和陶瓷材料，例如粉末冶金（P/M），金属注塑成型（MIM）和野外辅助烧结（快速）。总体而言，SSS平台是有利的，因为它们不需要高温才能完全融化金属或陶瓷粉末，这意味着通过烧结而不是通过其他标准处理方法来制造零件所需的能量。但是，烧结仍然存在长期存在的挑战，包括孔隙率，收缩和最终形状的其他变化等问题，由于在微观和纳米范围内发生的事件不容易预测，而这些事件尚未得到充分了解。该研究项目正在通过直接成像粉末表面和使用高功率的X射线实验和高放大倍倍电子显微镜实时成像粉末表面和粉末的内部结构来揭示跨多个长度尺度的基本烧结机制。这些最新的方法正在提供有关缺陷形式以及内部结构如何变化的新知识。 Binder Jet 3D打印（BJ3DP）被用作示例过程，因为BJ3DP对汽车行业具有重大兴趣，但是研究结果为各种SSS应用程序有助于新的设计策略。该项目还促进了对高级制造业的本科生和研究生的培训，以解决美国当前和不断增长的技能差距，这是通过使学生接触到最先进的特征工具，使他们参与制造研究，并使他们参与自动性行业的工业合作伙伴的专业发展机会。此外，该项目正在通过招募和心理化的研究生从代表性不足的人群中招募和心理化，并为K-12年级的学生与密歇根大学自然历史博物馆合作，为K-12年级的学生提供手工跨社区外展活动。技术摘要。支持内部微结构发展的主要机制。由于可以通过至少六种不同且潜在的竞争机制制备烧结的总体驱动力（减少界面表面能量），因此对SSS的强烈理解在很大程度上受到了缺乏原位数据的困扰。这项研究采用了新型的原位X射线计算机断层扫描（XCT）和高能量衍射显微镜（HEDM）直接对3D粒子进行成像和内部微结构进化，并在新颖的Binder Jet 3D打印（BJ3DP）中使用微米尺度分辨率进行微分尺度分辨率。 Binder Jet由于其在汽车行业的强大实施潜力而被用作示例。结果与电子显微镜结合使用，以了解SSS工作期间工作中的主要扩散机制，以及它们如何受过程，原料和/或材料因素的影响。调查结果用于测试BJ3DP中致密化和晶粒生长的基本假设，并用作基于物理模型的校准数据。总体而言，这种新知识正在增强对适用于各种具有强大工业相关性的SSS过程的微观结构进化的预测，例如粉末冶金，金属注塑成型和现场辅助烧结。正在使用综合教育模块来通过针对本科生和研究生的研究经验来减少美国当前不断增长的制造技能差距，并为汽车行业的学生提供专业发展机会。教育和外展活动包括积极招募和培训代表性不足的少数群体和妇女，并与U-M自然历史博物馆合作为K-12的学生提供可访问的动手活动，以激发对先进制造和STEM的兴趣。这奖反映了NSF的立法使命，并通过使用基金会的智力效果进行评估，以评估值得评估，并具有值得的评估。