Fundamental Study of Low-Cycle-Fatigue Behavior of High-Entropy Alloys

高熵合金低周疲劳行为的基础研究

• 批准号: 1611180
• 负责人: Peter Liaw
• 金额: $ 42万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1611180&HistoricalAwards=false
• 关键词: Fundamental; Study; Low; Cycle; Fatigue

Non-Technical AbstractThis project will study low-cycle-fatigue behavior of a new class of multi-component alloys called high-entropy alloys. These alloys have attracted huge attention in recent five years for their unique mechanical properties. The transformative potential of the present work is represented as a systematic and innovative investigation for structural characterization experiments, thus revealing the deformation mechanisms under cyclic loading and integrating the design, fabrication, verification, improvement, and prediction components, which can be applied for the studies of other advanced materials in the future. Students and researchers involved in this project will have opportunities to experience the state-of-the-art research equipment at the national laboratories. The outreach activities will include the K-12 science education, minority involvement, and efforts to engage the public. The results of the project will be disseminated through avenues accessible to the scientific community and to the general public with an emphasis on middle- and high-school students, as well as women and minority students. Appropriate aspects of the research results will be incorporated into the principal investigator's (PI's) graduate and undergraduate course materials to introduce students to modern interdisciplinary materials research. Technical AbstractThe goal of this project is to (1) study the low-cycle fatigue (LCF) behavior of high-entropy alloys (HEAs) by varying the structures (e.g., controlling the Al content), (2) clarify the deformation mechanisms of HEAs during LCF using state-of-art characterization methods (e.g., advanced microscopy and in-situ neutron diffraction), and (3) based on the fundamental understanding of the deformation behavior obtained from the present work, design and develop innovative HEAs with excellent LCF properties. HEAs attract huge attention in recent five years for their unique and excellent mechanical properties. Even though extensive studies have been devoted to the mechanical behavior,most of these research activities are for monotonic tests and almost none has focused on the fatigue properties, especially LCF. The mechanism of fatigue behavior must be examined carefully before HEAs can indeed be introduced in practical applications. The critical issues, thus, become obvious: (1) how do the multi-principal elements affect structures, and further, fatigue properties; (2) how does the high-entropy configuration influence the deformation mechanism; and (3) if the above two aspects have positive effects on the fatigue resistance, what are the fundamental contributing factors. Accordingly, a hypothesis is proposed and to be tested in the present work that HEAs with some specific compositions (i.e., structures) will show superior fatigue resistance over traditional alloys due to (1) great tendency to form twins, (2) solute atoms and large distortion from the element-size mismatch to pin dislocations, and (3) the interaction between dislocation and twinning, before fatigue-crack initiation and during crack propagation at room and elevated temperatures, and their long-term performance can be modulated and further improved by cold or hot treatment (e.g., cold rolling to control grain size). It is expected that the mechanism of LCF behavior could be revealed by a combination of the proposed experimental, theoretical, and modeling efforts, thus providing the fundamental understanding of the deformation behavior for single- and multiple-phase HEAs.

非技术摘要该项目将研究一种称为高熵合金的新型多组分合金的低周疲劳行为。近五年来，这些合金因其独特的机械性能而引起了极大的关注。目前工作的变革潜力表现为对结构表征实验的系统性和创新性研究，从而揭示循环载荷下的变形机制，并集成设计、制造、验证、改进和预测组件，可应用于研究未来其他先进材料的应用。 参与该项目的学生和研究人员将有机会体验国家实验室最先进的研究设备。外展活动将包括 K-12 科学教育、少数族裔参与以及公众参与的努力。该项目的成果将通过科学界和公众的渠道进行传播，重点关注初中生和高中生以及女性和少数民族学生。研究成果的适当方面将纳入首席研究员（PI）的研究生和本科生课程材料中，以向学生介绍现代跨学科材料研究。 技术摘要该项目的目标是（1）通过改变结构（例如控制铝含量）来研究高熵合金（HEA）的低周疲劳（LCF）行为，（2）阐明高熵合金的变形机制LCF 过程中使用最先进的表征方法（例如先进显微镜和原位中子衍射）进行 HEA，以及 (3) 基于从当前工作中获得的对变形行为的基本了解，设计和开发创新的 HEA具有优异的LCF特性。近五年来，HEA以其独特且优异的机械性能引起了人们的广泛关注。尽管对机械行为进行了广泛的研究，但这些研究活动大多数都是单调测试，几乎没有关注疲劳性能，尤其是 LCF。在将 HEA 真正引入实际应用之前，必须仔细研究疲劳行为的机制。因此，关键问题变得显而易见：（1）多主元如何影响结构，进而影响疲劳性能； (2)高熵构型如何影响变形机制； (3)如果上述两方面对抗疲劳性能产生积极影响，那么根本的影响因素是什么？因此，提出了一个假设并在目前的工作中进行测试，即具有某些特定成分（即结构）的 HEA 将比传统合金表现出优异的抗疲劳性，因为（1）形成孪晶的倾向很大，（2）溶质原子和单元尺寸失配到销位错造成的大变形，以及（3）在疲劳裂纹萌生之前以及室温和高温下裂纹扩展期间位错和孪生之间的相互作用，以及它们的长期性能可以调节和进一步改善因寒冷或热处理（例如冷轧以控制晶粒尺寸）。预计 LCF 行为的机制可以通过所提出的实验、理论和建模工作的结合来揭示，从而提供对单相和多相 HEA 变形行为的基本理解。

项目成果

Effects of Constituent Elements and Fabrication Methods on Mechanical Behavior of High-Entropy Alloys: A Review

成分元素和制造方法对高熵合金力学行为的影响：综述

• DOI: 10.1007/s11661-018-4970-z
• 发表时间: 2018-10-25
• 期刊: Metallurgical and Materials Transactions A
• 作者: Z. Lyu;Chanho Lee;Shao;Xuesong Fan;J. Yeh;P. Liaw
• 通讯作者: P. Liaw

Fundamental electronic structure and multiatomic bonding in 13 biocompatible high-entropy alloys

13种生物相容性高熵合金的基本电子结构和多原子键合

• DOI: 10.1038/s41524-020-0321-x
• 发表时间: 2020-05-06
• 期刊: npj Computational Materials
• 影响因子: 9.7
• 作者: W. Ching;Saro San;J. Brechtl;R. Sakidja;Miqin Zhang;P. Liaw
• 通讯作者: P. Liaw

Tensile creep behavior of an equiatomic CoCrNi medium entropy alloy

等原子CoCrNi中熵合金的拉伸蠕变行为

• DOI: 10.1016/j.intermet.2020.106775
• 发表时间: 2020-06-01
• 期刊: Intermetallics
• 影响因子: 4.4
• 作者: D. Xie;R. Feng;P. Liaw;H. Bei;Yanfei Gao
• 通讯作者: Yanfei Gao

First-principles and machine learning predictions of elasticity in severely lattice-distorted high-entropy alloys with experimental validation

严重晶格畸变高熵合金弹性的第一原理和机器学习预测并经过实验验证

• DOI: 10.1016/j.actamat.2019.09.026
• 发表时间: 2019-12
• 期刊: Acta Materialia
• 影响因子: 9.4
• 作者: Kim, George;Diao, Haoyan;Lee, Chanho;Samaei, A.T.;Phan, Tu;de Jong, Maarten;An, Ke;Ma, Dong;Liaw, Peter K.;Chen, Wei
• 通讯作者: Chen, Wei

Novel NiAl-strengthened high entropy alloys with balanced tensile strength and ductility

具有平衡拉伸强度和延展性的新型 NiAl 强化高熵合金

• DOI: 10.1016/j.msea.2018.11.055
• 发表时间: 2019-01-01
• 期刊: Materials Science and Engineering: A
• 作者: H. Diao;D. Ma;R. Feng;Tingkun Liu;Chao Pu;Chuan Zhang;W. Guo;J. Poplawsky;Yanfei Gao
• 通讯作者: Yanfei Gao