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Mechanistic Understanding of Multi-scale Sintering Behavior Influenced by Anisotropic Particle and Pore Distributions in Extrusion-based Metal Additive Manufacturing

基于挤压的金属增材制造中受各向异性颗粒和孔隙分布影响的多尺度烧结行为的机理理解

基本信息

批准号：
2224309
负责人：
Fuda Ning
金额：
$ 49.6万
依托单位：
SUNY at Binghamton
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2023
资助国家：
美国
起止时间：
2023-01-01 至 2025-12-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2224309&HistoricalAwards=false
关键词：
Mechanistic Understanding Multi scale Sintering

项目摘要

Without melting materials, metal additive manufacturing can also be achieved by first extruding filaments (in a 3D printing fashion) that contain densely filled metallic particles and polymetric binders, to form the so-called green parts, and then undergoing debinding and sintering to produce finished metal components. This relatively new metal additive manufacturing process nonetheless has technical challenges too including element segregations occurred in sintering and printing-induced anisotropic particle distributions that complicate the prediction of resultant micro- and macro-structures. This award supports fundamental research to understand the multi-scale underlying mechanisms occurred in sintering 3D filament-printed stainless steel parts using a combination of multi-physics simulations, analytical modeling, and experimental characterization and testing. The approach of extrusion-printing, debinding and sintering features ease of part handling and reduction of production costs, especially for large-sized metal component fabrications. The knowhow of this metal additive manufacturing technology will heighten manufacturing competitiveness in key industries such as aerospace, energy, automotive, and defense. The project will promote the participation of underrepresented groups such as African American and female students through summer research immersion programs. The research findings will be spread to local K-12 students through onsite interactive demonstrations and virtual micro-learning videos, also to the industry and community through an additive manufacturing symposium at Binghamton University.The overall goal of this research is to establish a fundamental understanding of the mechanisms that govern anisotropic sintering behaviors at atomistic, microscopic, and macroscopic scales during extrusion-printing, debinding and sintering of stainless steel parts. The interactions between atomic diffusion and multi-element redistribution will first be discovered by molecular dynamics simulations to examine the dominant mechanism that affects the grain boundary migration at the atomic scale. The team will then uncover the microscale pore distribution and grain evolution with sintering temperatures and times using approaches like discrete element method, in which temperature-dependent diffusion parameters determined from molecular dynamics will be incorporated to derive particle contact evolution and grain growths during sintering. A constitutive model will be developed to calculate the macro-scale anisotropic shrinkage and distortions during sintering. The prediction of element segregation, grain-boundary defects, pore distribution, grain size, and anisotropic deformation of sintered specimens will be experimentally validated by material characterizations, including x-ray computed tomography, complemented by measuring the resultant mechanical properties of sintered specimens. The project will also establish a semi-empirical process-structure-property relationship to guide the fabrication of stainless steel parts with desired properties. This findings are expected to advance the design, fabrication, and application of alloys with predictable microstructures and macroscopic characteristics as well as tailorable mechanical performance.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.

在不熔化材料的情况下，金属增材制造也可以通过首先挤压包含密集填充的金属颗粒和聚合物粘合剂的长丝（以3D打印方式）来实现，形成所谓的绿色部件，然后进行脱脂和烧结以生产成品金属部件。尽管如此，这种相对较新的金属增材制造工艺也存在技术挑战，包括在烧结和打印诱导的各向异性颗粒分布中发生的元素分离，使最终微观和宏观结构的预测复杂化。该奖项支持基础研究，以了解在烧结3D长丝打印不锈钢部件中发生的多尺度潜在机制，使用多物理场模拟，分析建模，实验表征和测试相结合。挤压打印，脱脂和烧结的方法具有易于零件处理和降低生产成本的特点，特别是对于大型金属部件制造。这种金属增材制造技术的专有技术将提高航空航天、能源、汽车和国防等关键行业的制造业竞争力。该项目将通过暑期浸入式研究项目，促进非裔美国人和女学生等代表性不足群体的参与。研究成果将通过现场互动演示和虚拟微型学习视频传播给当地K-12学生，并通过宾厄姆顿大学的增材制造研讨会传播给行业和社区。本研究的总体目标是建立一个基本的机制，控制各向异性的烧结行为在原子，微观和宏观尺度在挤压打印，脱脂和不锈钢零件的烧结。原子扩散和多元素再分配之间的相互作用将首先通过分子动力学模拟来发现，以研究影响原子尺度晶界迁移的主要机制。然后，该团队将利用离散元法等方法揭示微观尺度的孔隙分布和晶粒随烧结温度和时间的演变，其中由分子动力学确定的温度相关扩散参数将被纳入烧结过程中颗粒接触演变和晶粒生长。本构模型将用于计算烧结过程中宏观尺度的各向异性收缩和变形。元素偏析、晶界缺陷、孔隙分布、晶粒尺寸和烧结试样的各向异性变形的预测将通过材料表征（包括x射线计算机断层扫描）进行实验验证，并通过测量烧结试样的最终力学性能加以补充。该项目还将建立半经验的工艺-结构-性能关系，以指导具有所需性能的不锈钢零件的制造。这一发现有望推动具有可预测的微观结构和宏观特征以及可定制的机械性能的合金的设计、制造和应用。该奖项反映了美国国家科学基金会的法定使命，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。