Understanding the Hardening Mechanisms Associated with Short-Range Atom Clusters in High Entropy Alloys

了解高熵合金中与短程原子团簇相关的硬化机制

• 批准号: 1810720
• 负责人: Ting Zhu
• 金额: $ 33.18万
• 依托单位: Georgia Tech Research Corporation
• 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: 2019-04-15 至 2023-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1810720&HistoricalAwards=false
• 关键词: Understanding; Hardening; Mechanisms; Associated; Short

NONTECHNICAL SUMMARYThis award supports theoretical and computational research and education on mechanical behaviors of metallic materials. Metals and alloys are the workhorse materials for the manufacturing industry and structural applications. This is mainly because they have a good balance of strength, a metal's resistance to deformation and failure, and ductility, a metal's ability to undergo irreversible deformation before rupture. Usually there is a strength-ductility tradeoff, a gain in strength in a material is inevitably accompanied by a sacrifice in ductility. High entropy alloys are a new class of materials that contain nearly equal numbers of atoms of five or more different elements. Their unconventional concentrated multiple element compositions hold promise for achieving an exceptional combination of strength and ductility. However, the fundamental mechanisms that control the strength and ductility in high entropy alloys down to the atomic scale remain largely unexplored. This project focuses on investigation of the microscopic deformation mechanisms in high entropy alloys. Effects of the composition fluctuations on deformation processes mediated by defects in the periodic arrangement of atoms in the alloy will be studied by computer simulations on the scale of atoms; the results will be further compared with experiments. The physical insights gained will be important for guiding the future development of new high entropy alloys with a superior strength-ductility combination. The project will foster collaborations between theory and experiment. Educational activities will offer opportunities to introduce students to computer modeling techniques for simulating materials and to inspire students to pursue careers in science and engineering.TECHNICAL SUMMARYThis award supports theoretical and computational research and education to advance the fundamental understanding of deformation mechanisms in high entropy alloys. Strength and ductility are among the most important mechanical properties of metals and alloys for engineering applications. High entropy alloys contain high concentrations of five or more different elements in near equiatomic proportions. The mechanisms controlling the strength and ductility of high entropy alloys remain poorly understood. This project is focused on understanding the mechanistic role of short-range clusters in the strain hardening and tensile ductility of face-centered cubic high entropy alloys. Multi-component interatomic potentials will be used to perform molecular dynamics and atomistic reaction pathway simulations for studying the dislocation pinning and cross-slip processes mediated by short-range clusters. Effects of stress, temperature, cluster size and density will be investigated. The modeling results will be compared with experimental characterizations of dislocation mechanisms and deformation microstructures. The insights gained are important for harnessing the short-range clusters to achieve a superior strength-ductility combination in high entropy alloys. The project will introduce advanced modeling techniques to students. The research results will be incorporated into a high-school course module as well as a graduate course on micromechanics. Undergraduate students will be involved in the research. These educational activities are aimed to inspire students to pursue careers in science and engineering.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.

该奖项支持金属材料力学行为的理论和计算研究和教育。金属和合金是制造业和结构应用的主力材料。这主要是因为它们具有良好的强度平衡，金属对变形和失效的抵抗力，以及延展性，金属在断裂前经历不可逆变形的能力。通常存在强度-延展性的折衷，材料强度的增加不可避免地伴随着延展性的牺牲。高熵合金是一种新的材料，含有几乎相等数量的五种或五种以上不同元素的原子。其非常规的浓缩多元素组合物有望实现强度和延展性的卓越组合。然而，控制高熵合金的强度和延展性的基本机制在原子尺度上仍然没有被探索。本计画主要研究高熵合金的微观变形机制。将通过原子尺度的计算机模拟研究合金中原子周期性排列缺陷对变形过程的影响;将进一步将结果与实验进行比较。获得的物理见解将是重要的指导未来发展的新的高熵合金与上级强度-延展性的组合。该项目将促进理论和实验之间的合作。教育活动将为学生提供机会，介绍计算机模拟材料的建模技术，并激励学生追求科学和工程的职业生涯。技术总结该奖项支持理论和计算研究和教育，以促进对高熵合金变形机制的基本理解。强度和延展性是工程应用中金属和合金最重要的机械性能之一。高熵合金包含五种或五种以上不同元素的高浓度，接近等原子比例。控制高熵合金强度和延展性的机制仍然知之甚少。这个项目的重点是理解短程团簇在面心立方高熵合金的应变硬化和拉伸延展性中的机械作用。多组分原子间相互作用势将被用于进行分子动力学和原子反应途径模拟，以研究短程团簇介导的位错钉扎和交叉滑移过程。将研究应力、温度、团簇大小和密度的影响。模拟结果将与位错机制和变形组织的实验表征进行比较。所获得的见解是重要的利用短程集群，以实现一个上级的强度和延展性的组合在高熵合金。该项目将向学生介绍先进的建模技术。研究结果将纳入一个高中课程单元以及一个关于微观力学的研究生课程。本科生将参与研究。这些教育活动旨在激励学生追求科学和工程事业。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。

项目成果

Trans-twin dislocations in nanotwinned metals

• DOI: 10.1016/j.scriptamat.2023.115348
• 发表时间: 2023-02-16
• 期刊: SCRIPTA MATERIALIA
• 影响因子: 6
• 作者: Bu, Linfeng;Cheng, Zhao;Lu, Lei
• 通讯作者: Lu, Lei

Unraveling dual phase transformations in a CrCoNi medium-entropy alloy

• DOI: 10.1016/j.actamat.2021.117112
• 发表时间: 2021-06-30
• 期刊: ACTA MATERIALIA
• 影响因子: 9.4
• 作者: Chen, Yujie;Chen, Dengke;Xie, Zonghan
• 通讯作者: Xie, Zonghan

Learning constitutive relations of plasticity using neural networks and full-field data

• DOI: 10.1016/j.eml.2022.101645
• 发表时间: 2022-02
• 期刊: Extreme Mechanics Letters
• 影响因子: 4.7
• 作者: Yin Zhang;Qing‐Jie Li;Ting Zhu;Ju Li

Strong yet ductile nanolamellar high-entropy alloys by additive manufacturing

• DOI: 10.1038/s41586-022-04914-8
• 发表时间: 2022-08-03
• 期刊: NATURE
• 影响因子: 64.8
• 作者: Ren, Jie;Zhang, Yin;Chen, Wen
• 通讯作者: Chen, Wen

Microstructure and mechanical behavior of additively manufactured CoCrFeMnNi high-entropy alloys: Laser directed energy deposition versus powder bed fusion

• DOI: 10.1016/j.actamat.2023.118884
• 发表时间: 2023-03-31
• 期刊: ACTA MATERIALIA
• 影响因子: 9.4
• 作者: Liu, Yanfang;Ren, Jie;Chen, Wen
• 通讯作者: Chen, Wen