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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.

在没有熔化材料的情况下，金属添加剂的制造也可以通过首先挤压含有密集填充的金属颗粒和多金属粘结剂的长丝(以3D打印方式)，形成所谓的绿色部件，然后进行脱脂和烧结以产生成品金属部件来实现。然而，这种相对较新的金属添加剂制造工艺也存在技术挑战，包括在烧结和印刷引起的颗粒分布各向异性中发生的元素分离，这使得对所得到的微观和宏观结构的预测复杂化。该奖项支持基础研究，以结合多物理模拟、分析建模以及实验表征和测试来了解3D纤维印刷不锈钢部件烧结过程中发生的多尺度潜在机制。挤压-印刷、脱脂和烧结方法的特点是零件搬运容易，生产成本降低，特别是对于大型金属零件的制造。这种金属添加剂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竞争力。该项目将通过暑期研究沉浸计划促进非洲裔美国人和女性学生等代表不足的群体的参与。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的K-12学生，也将通过宾厄姆顿大学的添加剂制造研讨会传播给行业和社区。这项研究的总体目标是建立对不锈钢零件挤压-印刷、脱脂和烧结过程中原子、微观和宏观尺度各向异性烧结行为的基本理解。首先通过分子动力学模拟发现原子扩散和多元素再分布之间的相互作用，以考察在原子尺度上影响晶界迁移的主要机制。然后，该团队将使用离散单元法等方法揭示微尺度气孔分布和颗粒随烧结温度和时间的演变，其中将纳入从分子动力学确定的温度相关扩散参数，以推导出烧结过程中颗粒接触的演变和颗粒生长。建立了一个本构模型来计算烧结过程中的宏观各向异性收缩和变形。对烧结试件的元素偏析、晶界缺陷、气孔分布、晶粒度和各向异性变形的预测将通过材料表征(包括X射线计算机层析成像)进行实验验证，并通过测量烧结试件的力学性能来补充。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部件的制造。这一发现有望推动具有可预测微结构和宏观特征以及可定制机械性能的合金的设计、制造和应用。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。