Collaborative Research: Bridging the atomic scale and the mesoscale in the characterization of defect production and evolution in high entropy alloys

合作研究：在高熵合金缺陷产生和演化表征中连接原子尺度和介观尺度

基本信息

批准号：
2005064
负责人：
FARIDA SELIM
金额：
$ 28.02万
依托单位：
Bowling Green State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-06-01 至 2024-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2005064&HistoricalAwards=false
关键词：
Collaborative Research Bridging atomic scale

项目摘要

NON-TECHNICAL SUMMARYDeveloping high strength materials that can withstand significant amounts of radiation and deformation are critical to advance many technical applications, including efficient nuclear energy production and space exploration. High entropy alloys (HEAs) are emerging as promising high strength and radiation-resistant materials as HEAs contain a mix of many elements that disrupt the chemical ordering. The focus of this research is to gain fundamental understanding at the atomic level on how the complexity of chemical disorder interferes with the formation and evolution of undesirable defects that weakens the material. To gain these insights, state of the art analytical and imaging techniques will be used to reveal how an atomic sized defect in the material evolves and how the chemical disorder interferes and halts this undesirable process. Such insights are needed to develop the optimal alloys with high radiation resistance, high strength and high stability that would not only enable new advanced power generating technologies with high efficiency and low or zero carbon emission but more generally, could transform many technical fields related to energy and space. Students working on the project will develop in-depth understanding on chemistry and physics of materials and defects in solids and gain experience in important techniques in material science. International student exchange and national internship opportunities are offered to the graduate students involved in the project. A wide range of research opportunities and outreach activities are provided to undergraduates and high school students throughout the period of the project where participation of underrepresented groups are actively encouraged. TECHNICAL SUMMARYHigh entropy alloys (HEAs) are emerging as an outstanding class of materials due to their excellent mechanical properties and high radiation tolerance as a result of their unique electronic structure. Chemical disorder and compositional fluctuations in these alloys have large effects on energy dissipation and response to irradiation. While previous transmission electron microscopy (TEM) and other studies showed that damage accumulation was suppressed by increasing chemical disorder, they could not reveal vacancy clusters below 2 nm leaving critical gap in understanding defect formation and buildup in these alloys. The proposed research aims to experimentally monitor defect formation on atomistic scale and their buildup to large clusters and voids by combining in-situ and ex-situ positron annihilation spectroscopy (PAS) with in-situ and ex-situ TEM to capture isolated vacancies, small vacancy clusters, larger clusters and voids, thus bridge the gap between the atomic scale and mesoscale characterization of radiation induced defects in HEAs. The use of In-situ PAS and In-situ TEM measurements both coupled with ion irradiation offers a picture of the defect dynamics including production, annihilation and evolution, on atomic scale (for PAS) and mesoscale (for TEM). The proposed research is expected to reveal the effects of chemical disorder on defect formation, migration and evolution in a radiation environment and reveal the damage and annealing mechanisms in Single -Phase Concentrated Solid Solution alloys (SP-CSAs) and HEAs through the study of defect production from collision cascades on an atomic and mesoscale level in alloys with increasing chemical complexity from one to five constituents.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.

非技术摘要开发能够承受大量辐射和变形的高强度材料对于推进许多技术应用至关重要，包括高效核能生产和太空探索。高熵合金 (HEA) 正在成为一种有前途的高强度和抗辐射材料，因为 HEA 含有多种破坏化学有序的元素的混合物。这项研究的重点是在原子水平上获得关于化学无序的复杂性如何干扰削弱材料的不良缺陷的形成和演变的基本了解。为了获得这些见解，将使用最先进的分析和成像技术来揭示材料中原子大小的缺陷如何演变以及化学紊乱如何干扰和阻止这一不良过程。需要这些见解来开发具有高抗辐射性、高强度和高稳定性的最佳合金，这不仅可以实现高效率、低碳或零碳排放的新型先进发电技术，而且更广泛地说，可以改变与能源相关的许多技术领域和空间。从事该项目的学生将深入了解材料的化学和物理以及固体缺陷，并获得材料科学重要技术的经验。为参与该项目的研究生提供国际学生交流和国内实习机会。在整个项目期间，为本科生和高中生提供广泛的研究机会和外展活动，并积极鼓励代表性不足的群体参与。技术概要高熵合金 (HEA) 因其独特的电子结构而具有优异的机械性能和高辐射耐受性，正在成为一类杰出的材料。这些合金中的化学无序和成分波动对能量耗散和辐射响应有很大影响。虽然之前的透射电子显微镜 (TEM) 和其他研究表明，通过增加化学无序性可以抑制损伤积累，但它们无法揭示低于 2 nm 的空位簇，从而在理解这些合金中的缺陷形成和累积方面留下了关键差距。拟议的研究旨在通过将原位和异位正电子湮没光谱 (PAS) 与原位和异位 TEM 相结合，以实验方式监测原子尺度上的缺陷形成及其向大团簇和空隙的累积，以捕获孤立的空位、小缺陷。空位团簇、较大的团簇和空隙，从而弥合了 HEA 中辐射引起的缺陷的原子尺度和介观尺度表征之间的差距。原位 PAS 和原位 TEM 测量与离子辐照相结合，可以在原子尺度（对于 PAS）和介观尺度（对于 TEM）上提供缺陷动态图，包括产生、湮灭和演化。该研究有望揭示化学无序对辐射环境中缺陷形成、迁移和演化的影响，并通过缺陷研究揭示单相浓固溶体合金（SP-CSA）和HEA的损伤和退火机制该奖项反映了 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

期刊论文数量（8）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Light-driven permanent transition from insulator to conductor

DOI：
10.1103/physrevb.104.245208
发表时间：
2020-03
期刊：
Physical Review B
影响因子：
3.7
作者：
Farida Selim;D. Rana;S. Agarwal;Minhazul Islam;A. Banerjee;B. Uberuaga;P. Saadatkia;P. Dulal;N. Adhikari;M. Butterling;M. Liedke;Andreas Wagner
通讯作者：
Farida Selim;D. Rana;S. Agarwal;Minhazul Islam;A. Banerjee;B. Uberuaga;P. Saadatkia;P. Dulal;N. Adhikari;M. Butterling;M. Liedke;Andreas Wagner

Bridging the Atomic Scale and the Mesoscale in the Characterization of Defect Production and Evolution in High Entropy Alloys

在高熵合金缺陷产生和演化表征中连接原子尺度和介观尺度