Collaborative Research: Probing Particle Impact onto Molten Metal Pool in Laser Directed Energy Deposition by Synchrotron Imaging and Process Modeling

合作研究：通过同步加速器成像和过程建模探测激光定向能量沉积中的粒子对熔融金属池的影响

• 批准号: 2245141
• 负责人: Sarah Wolff
• 金额: $ 33.77万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-15 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2245141&HistoricalAwards=false
• 关键词: Collaborative; Research; Probing; Particle; Impact

Laser powder-fed directed energy deposition (LP-DED) is an additive manufacturing technology that is potentially capable of making functionally graded, multi-material parts with location-specific properties for a wide range of applications, including aerospace components, biomedical devices, and energy storage, etc. However, because of intertwined multi-physics phenomena and extreme length scales, how tiny fast-moving particles interact with a laser-melted metal pool in LP-DED is still little known, despite its strong influence to defect origination in fabricated parts. This collaborative research project aims to capture fundamental contacts between high-speed metal particles and a molten pool in LP-DED using synchrotron X-ray imaging complemented by comprehensive process modeling with a goal of better control in industrial-scale LP-DED processing. This award will also contribute to the workforce development of a diverse group of students, including opportunities with the National School on Neutron and X-ray Scattering for graduate students. In addition, the team will jointly host outreach events for girls and women that focus on additive manufacturing in the local community, including with the Women in 3D Printing, which will highlight many female experts in metal additive manufacturing.The objective of this collaborative project is fundamental understanding of the interactions between in-flight metal particles and a laser-generated molten pool, which affect liquid metal flows and entangle pore formation in LP-DED. The discovery-driven research is to test two hypotheses; 1) greater kinetic energy in particle impact will increase melt pool flow velocities and 2) an increase in melt pool flow velocities will decrease the amount of pore formation in LP-DED parts. The approach includes a custom-made operando LP-DED setup for synchrotron monitoring, where imaging will occur at a laser-induced melt pool with spatial and temporal resolutions of about 2 microns and 1 microsecond, respectively, precisely capturing in-situ the changes inside the melt pool when powder flows near and into the melt pool. In conjunction with synchrotron-based experiments, a computational fluid dynamics model and a discrete particle dynamics model will be coupled to simulate melt pool flow velocities and temperatures, as well as the motions in the melt pool due to particle impact and liquefying. Experiments will support calibration and validation of the multi-physics models, whereas the simulation results will estimate local flow velocities and surface tension to predict for pore formation and growth rooted from particle impact. The investigation of high-speed and small-scale observations will fill the knowledge gaps in how porosity occurs in LP-DED as well as why there are large variations in the microstructure, porosity, and mechanical behavior of LP-DED processed components.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.

激光送粉定向能量沉积 (LP-DED) 是一种增材制造技术，有可能制造具有特定位置属性的功能分级多材料零件，适用于广泛的应用，包括航空航天部件、生物医学设备和然而，由于相互交织的多物理现象和极端的长度尺度，微小的快速移动粒子如何与 LP-DED 中的激光熔化金属池相互作用仍然知之甚少，尽管它对缺陷起源有很大影响。制造零件。该合作研究项目旨在利用同步加速器 X 射线成像并辅以综合过程建模来捕获 LP-DED 中高速金属颗粒与熔池之间的基本接触，以更好地控制工业规模的 LP-DED 加工。该奖项还将促进多元化学生群体的劳动力发展，包括为研究生提供与国家中子和 X 射线散射学院合作的机会。此外，该团队还将与 Women in 3D Printing 联合举办针对当地社区增材制造的女孩和妇女外展活动，该活动将突出许多金属增材制造领域的女性专家。该合作项目的目标是对飞行中金属颗粒与激光生成熔池之间相互作用的基本了解，这种相互作用会影响 LP-DED 中的液态金属流动和缠结孔的形成。发现驱动的研究是为了检验两个假设； 1) 颗粒冲击中更大的动能将增加熔池流速，2) 熔池流速的增加将减少 LP-DED 零件中孔隙形成的数量。该方法包括用于同步加速器监测的定制操作 LP-DED 设置，其中成像将在激光诱导熔池中进行，空间和时间分辨率分别约为 2 微米和 1 微秒，精确捕获内部的原位变化当粉末流近并进入熔池时，熔池中的粉末会进入熔池。结合基于同步加速器的实验，将耦合计算流体动力学模型和离散粒子动力学模型来模拟熔池流速和温度，以及由于粒子撞击和液化而导致的熔池运动。实验将支持多物理模型的校准和验证，而模拟结果将估计局部流速和表面张力，以预测源自颗粒撞击的孔隙形成和生长。对高速和小规模观测的研究将填补 LP-DED 中孔隙如何发生以及为什么 LP-DED 加工部件的微观结构、孔隙率和机械行为存在较大变化的知识空白。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。