Transient Thermo-Fluid Behavior in Metal Laser Powder-Bed Fusion Process: Exploring the Size Effect in Making Small Features

金属激光粉末床熔融工艺中的瞬态热流体行为：探索制造小特征时的尺寸效应

• 批准号: 1921263
• 负责人: Kevin Chou
• 金额: $ 41.6万
• 依托单位: University of Louisville Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1921263&HistoricalAwards=false
• 关键词: Transient; Thermo; Fluid; Behavior; Metal

Metal additive manufacturing in the laser powder-bed fusion group has greatly enabled novel designs with sophisticated part geometry of cellular arrangements or optimized topology for applications like lightweight high-strength structures, nature-inspired biomedical implants and high-efficiency heat exchangers, etc. Such integrated design and manufacturing innovations have the potential to realize products that improve the quality of life and maturing the technological capability of the U.S. industry. However, in making components with complex geometries, there are many small features (e.g., 0.5 mm or less) which do not share the same processing characteristics as larger sized bulk components. These unknown characteristics pose difficulty in ensuring part quality and impedes adopting the laser powder-bed fusion to produce parts with delicate features. This award addresses the above-mentioned challenges by advancing the process science in tackling small length scales, where the process characteristics become sensitive to the feature dimensions. The fundamental science that needs to be explored is the time-varying response of the temperatures and the molten flows in high-power laser scanning of metallic particles of stochastic distributions during short scanning. Further, outreach activities with the Women in Manufacturing, Kentucky Chapter will establish a platform that helps engage women to promote a diverse manufacturing workforce.The goal of this project is to understand the size effect in the metal laser powder-bed fusion process, in particular, to elucidate the coupled dynamic thermal and fluid fields during the start and end of laser scanning. The research focuses on one-dimensional line scans, two-dimensional raster-area scans and three-dimensional individual strut fabrications for the process physics study, as well as lattice-included specimens for mechanical evaluations related to the small geometry and process conditions. A two-stage approach will be employed to numerically study the process: a discrete element method to simulate powder particle spreading and multi-physics modeling to simulate the thermo-fluid phenomena for single-track, single-layer as well as multi-layer single strut fabrications, with particular emphases in the melt-pool dynamic response and solidified morphology. The experimental study will employ a laser powder-bed fusion system using titanium alloyed powder to fabricate designed specimens, with melt pool measurements and microstructures analysis to validate the process model and quantify the size effect on process characteristics. The research, if successful, will unveil the basic comprehension of the thermal and fluid behavior during short-distance and small-area laser scanning. The knowledge obtained will be practical for effective additive manufacturing of complex geometry parts with improved and reliable quality.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.

激光粉末床熔融组中的金属增材制造极大地实现了具有蜂窝排列的复杂零件几何形状或优化拓扑的新颖设计，适用于轻质高强度结构、受自然启发的生物医学植入物和高效热交换器等。这种集成设计和制造创新有可能实现提高生活质量和成熟美国工业技术能力的产品。然而，在制造具有复杂几何形状的组件时，存在许多小特征（例如 0.5 毫米或更小），这些特征与较大尺寸的散装组件不具有相同的加工特性。这些未知的特性给确保零件质量带来了困难，并阻碍了采用激光粉末床熔合来生产具有精细特征的零件。该奖项通过推进处理小长度尺度的工艺科学来解决上述挑战，其中工艺特性对特征尺寸变得敏感。需要探索的基础科学是短扫描期间随机分布的金属颗粒的高功率激光扫描中温度和熔体流动的时变响应。此外，与肯塔基州制造业女性分会的外展活动将建立一个平台，帮助女性促进多元化的制造业劳动力。该项目的目标是了解金属激光粉末床融合过程中的尺寸效应，特别是阐明激光扫描开始和结束期间耦合的动态热场和流体场。该研究的重点是用于过程物理研究的一维线扫描、二维光栅区域扫描和三维单独支柱制造，以及用于与小几何形状和工艺条件相关的机械评估的包含晶格的样本。将采用两阶段方法对该过程进行数值研究：采用离散元方法模拟粉末颗粒扩散，采用多物理场建模模拟单轨、单层以及多层单支柱制造的热流体现象，特别强调熔池动态响应和凝固形态。该实验研究将采用激光粉末床熔融系统，使用钛合金粉末制造设计的样品，并通过熔池测量和微观结构分析来验证工艺模型并量化尺寸对工艺特性的影响。该研究如果成功，将揭示对短距离和小面积激光扫描期间热和流体行为的基本理解。所获得的知识对于复杂几何零件的有效增材制造具有实用性，并且具有改进和可靠的质量。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。

项目成果

Build surface study of single-layer raster scanning in selective laser melting: Surface roughness prediction using deep learning

选择性激光熔化中单层光栅扫描的构建表面研究：使用深度学习预测表面粗糙度

• DOI: 10.1016/j.mfglet.2022.07.088
• 发表时间: 2022
• 期刊: Manufacturing Letters
• 影响因子: 3.9
• 作者: Fotovvati, Behzad;Chou, Kevin
• 通讯作者: Chou, Kevin

Multi-layer thermo-fluid modeling of powder bed fusion (PBF) process

粉末床熔融 (PBF) 过程的多层热流体建模

• DOI: 10.1016/j.jmapro.2022.09.003
• 发表时间: 2022
• 期刊: Journal of Manufacturing Processes
• 影响因子: 6.2
• 作者: Fotovvati, Behzad;Chou, Kevin
• 通讯作者: Chou, Kevin

An Investigation Into Multi-Track Deposition in Laser Powder-Bed Fusion: Transient Regions Analysis and Scan Length Effects

激光粉末床融合中多轨沉积的研究：瞬态区域分析和扫描长度效应

• 发表时间: 2022
• 期刊: MSEC2022-85746
• 作者: Rauniyar, S.;Shrestha, S.;Chou, K
• 通讯作者: Chou, K

Transient Melt Pool Formation in Laser-Powder Bed Fusion Process

激光粉末床熔融过程中瞬态熔池的形成

• 发表时间: 2020
• 期刊: Proceedings of the ASME 2020 15th International Manufacturing Science and Engineering Conference
• 作者: Rauniyar, S.;Chou, K.
• 通讯作者: Chou, K.