CAREER: Unraveling Fundamental Mechanisms Governing Grain Refinement in Complex Concentrated Alloys Made by Additive Manufacturing Towards Strong and Ductile Structures

职业：揭示增材制造复杂浓缩合金晶粒细化的基本机制，以获得坚固且延展的结构

• 批准号: 2047218
• 负责人: Wei Xiong
• 金额: $ 52.63万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-15 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2047218&HistoricalAwards=false
• 关键词: CAREER; Unraveling; Fundamental; Mechanisms; Governing

The ability to produce strong yet tough structural alloys has been a quest to fully exploit the integrated innovation of materials and manufacturing. One longstanding challenge is the well-known strength-ductility trade-off; the stronger a given material is, the less ductile it becomes. Grain structure refinements have been studied for conventional alloys to enhance both the strength and ductility. To date, however, it remains unclear how grain refinements may be effectively applied to complex concentrated alloys (CCAs), which are compositionally compound with multiple principal chemical elements, made by additive manufacturing. This Faculty Early Career Development (CAREER) award supports fundamental investigations into additive manufacturing of CCAs. The project will perform different studies to test a hypothesis that increasing the entropy (i.e., level of disorder) in an alloy system will retard grain coarsening and stabilize microstructures, and thus, achieve both great strengths and high ductility. The research findings will bridge the knowledge gaps of microstructure engineering in designs and additively manufacturing of CCAs for high temperature and other critical applications. In concert, the formulated outreach activities will advance the research and educations in training the next generation of researchers and STEM leaders in advanced manufacturing, specifically fostering inclusions of women and minorities in manufacturing and related fields.The overarching goal of this research is to understand the underlying mechanism of grain refinements in CCAs made by additive manufacturing through a mixture of dissimilar alloy powders and subsequent melting and solidifying. The project will investigate grain growth kinetics and phase stability in complex composition space, using an effective research toolkit comprised of machine-learning enhanced modeling, high-throughput fabrication experiments, as well as microstructural and material characterizations. This research will address knowledge needs related to microstructure engineering for the additive manufacturing of CCAs by exploring microstructure configurations generated from dissimilar alloy using powder-based additive manufacturing technologies (directed energy deposition and powder-bed fusion, both using a laser heat source) with following expected outcomes: (i) quantification of alloy entropy effects on process-structure-property relationships to reveal the fundamental mechanism to strengthen CCAs with refined grains or other means, (ii) microstructure formation in CCAs to understand the difference between complex concentrated vs. traditional alloys made by powder based additive manufacturing, and (iii) process-structure-property models to establish specifically for CCAs in the composition space between stainless steels and nickel-based superalloys.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.

生产坚固而坚韧的结构合金的能力一直是充分利用材料和制造的集成创新的追求。众所周知的强度与延展性权衡是一项长期存在的挑战。给定材料的强度越高，其延展性就越差。人们已经研究了传统合金的晶粒结构细化，以提高强度和延展性。 然而，迄今为止，尚不清楚如何有效地将晶粒细化应用于复杂浓缩合金（CCA），这些合金由多种主要化学元素组成，通过增材制造制成。该学院早期职业发展 (CAREER) 奖项支持对 CCA 增材制造的基础研究。该项目将进行不同的研究来检验一个假设，即增加合金系统的熵（即无序程度）将延缓晶粒粗化并稳定微观结构，从而实现高强度和高延展性。研究结果将弥补高温和其他关键应用的 CCA 设计和增材制造方面的微结构工程知识差距。同时，制定的外展活动将推动研究和教育，培训下一代先进制造业研究人员和 STEM 领导者，特别是促进妇女和少数族裔参与制造业及相关领域。这项研究的总体目标是了解CCA 晶粒细化的基本机制是通过增材制造通过不同种合金粉末的混合物以及随后的熔化和凝固而制成的。该项目将使用由机器学习增强建模、高通量制造实验以及微观结构和材料表征组成的有效研究工具包，研究复杂成分空间中的晶粒生长动力学和相稳定性。本研究将通过探索使用粉末增材制造技术（定向能量沉积和粉末床熔合，均使用激光热源）从异种合金生成的微结构配置，解决与 CCA 增材制造的微结构工程相关的知识需求，具体如下预期成果：(i) 量化合金熵对工艺-结构-性能关系的影响，以揭示通过细化晶粒或其他方式强化 CCA 的基本机制，(ii) CCA 中的微观结构形成，以了解复杂浓缩与传统浓缩之间的差异粉末基增材制造制成的合金，以及 (iii) 专门为不锈钢和镍基高温合金之间的成分空间中的 CCA 建立工艺-结构-性能模型。该奖项反映了 NSF 的法定使命，并被认为值得通过以下方式获得支持：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。

项目成果

Exploring Alloy Design Pathway Through Directed Energy Deposition of Powder Mixtures: A Study of Stainless Steel 316L and Inconel 718

• DOI: 10.1016/j.addlet.2023.100133
• 发表时间: 2023-02
• 期刊: Additive Manufacturing Letters
• 作者: Noah Sargent;Yuankang Wang;Daozheng Li;Yunhao Zhao;Xin Wang;W. Xiong

Additive manufacturing as a tool for high-throughput experimentation

• DOI: 10.20517/jmi.2022.19
• 发表时间: 2022
• 期刊: Journal of Materials Informatics
• 作者: W. Xiong