Collaborative Research: Coordinated In-situ Dynamic Experiments and Atomistic Modeling of Surface Segregation in Alloys

合作研究：合金表面偏析的协调原位动态实验和原子建模

• 批准号: 1905572
• 负责人: Guofeng Wang
• 金额: $ 20万
• 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: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1905572&HistoricalAwards=false
• 关键词: Collaborative; Research; Coordinated; situ; Dynamic

Non-technical abstract:Surface segregation phenomena - the enrichment of one element at the surface relative to the bulk - have enormous consequences in many areas of materials science because most engineering materials are alloys either by design for improving properties or by impurities remaining after processing or by contamination from the surrounding. Often, minor compositional modifications that occur locally in a material can lead to drastic changes in properties such as corrosion resistance, catalytic function, fracture strength, and interfacial adhesion. This project seeks to uncover the dependence of surface segregation on controllable parameters such as bulk composition, surface orientation and morphology, and external stimuli as well as the microscopic mechanism of the surface segregation process. The fundamental insight will have considerable practical importance for a wide range of material systems, properties, and reactions because segregation not only modifies surface chemistry and composition but also the atomic structure and strain state in the surface and subsurface regions in multicomponent materials. The fundamental knowledge of the prototypes of basic processes controlling surface composition and structure evolution will open up new perspectives of designing alloys with desired surface properties by manipulating bulk properties of the alloy and their interplay with the surroundings. As part of this research program, students at the graduate and undergraduate levels will learn about new microscopy, spectroscopy and computational techniques as well as work on materials issues that are at the forefront of current materials research. The training of students in the broader area of materials science will result in future leaders that are better equipped to solve the complex energy and environmental problems that face society. Results from this project will also be incorporated into undergraduate- and graduate-level courses and high school outreach programs to advance nanomaterials-related education.Technical abstract: Although phase diagrams delineating the thermodynamic conditions for phase/structure selection in bulk alloys are well established, the composition and structure of an alloy surface can be significantly different from those of the bulk due to the surface segregation of the alloying element. A microscopic understanding of many physical and chemical processes taking place at the surface of multicomponent materials requires as a prerequisite atomic-scale understanding of surface segregation induced compositional and structural evolution. Despite this importance, the atomic processes governing the onset, promotion, and termination of surface segregation under practical conditions are largely unknown. This project employs atomistically informed approaches toward a mechanistic understanding of surface segregation phenomena by gaining transformational knowledge of surface compositional and structural dynamics of alloys. The research is based on a combined atomistic experimental and computational program with tightly integrated feedback loops, including quantitative in-situ metrology that uses complementary forefront techniques for dynamically measuring surface composition, structure and chemistry of the alloys under realistic environment conditions and closely coordinated atomistic modeling ranging from first-principles calculations to large-scale molecular dynamics and Monte Carlo simulations. The comprehensive understanding will shed light on many multicomponent systems due to a shared set of prototypical basic processes governing surface segregation, including thermodynamic driving forces, interplay between chemical ordering and elemental segregation, and kinetic obstacles of atomic exchanges.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：表面种族隔离现象 - 一个元素在表面相对于散装的富集 - 在许多材料科学领域都产生巨大后果，因为大多数工程材料都是通过设计来改善性质或在处理后或通过周围污染的杂质而设计的合金。通常，在材料中局部发生的次要组成修饰会导致诸如耐腐蚀性，催化功能，断裂强度和界面粘附等性能的急剧变化。该项目旨在发现表面隔离对可控参数的依赖性，例如散装组成，表面取向和形态，外部刺激以及表面分离过程的显微镜机制。基本洞察力对于广泛的材料系统，特性和反应将具有相当大的实际重要性，因为隔离不仅修饰了表面化学和组成，而且还改变了多组分材料中表面和地下区域的原子结构和应变状态。控制表面组成和结构演化的基本过程原型的基本知识将通过操纵合金的块状特性及其与周围环境的相互作用来打开具有所需表面特性的合金的新观点。作为该研究计划的一部分，研究生和本科级别的学生将了解新的显微镜，光谱和计算技术，以及在当前材料研究最前沿的材料问题上的工作。在更广泛的材料科学领域的学生培训将导致未来的领导者更好地解决面对社会面临的复杂能量和环境问题。该项目的结果还将纳入本科和研究生水平的课程以及高中宣传计划，以推进与纳米材料相关的教育。技术摘要：尽管相位图确定了相同合金中相位/结构选择的热力学条件的相位图，但与这些表面的组成和结构相差很大。对多组分材料表面发生的许多物理和化学过程的微观理解需要作为对表面隔离引起的成分和结构演化的先决条件的理解。尽管这一点很重要，但在实际条件下表面隔离的发作，促进和终止的原子过程在很大程度上是未知的。该项目通过获得对合金的表面组成和结构动力学的转化知识，采用原子知情的方法来对表面隔离现象的机械理解。 The research is based on a combined atomistic experimental and computational program with tightly integrated feedback loops, including quantitative in-situ metrology that uses complementary forefront techniques for dynamically measuring surface composition, structure and chemistry of the alloys under realistic environment conditions and closely coordinated atomistic modeling ranging from first-principles calculations to large-scale molecular dynamics and Monte Carlo simulations. The comprehensive understanding will shed light on many multicomponent systems due to a shared set of prototypical basic processes governing surface segregation, including thermodynamic driving forces, interplay between chemical ordering and elemental segregation, and kinetic obstacles of atomic exchanges.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 标准。

项目成果

High-entropy nanoparticles: Synthesis-structure-property relationships and data-driven discovery

高熵纳米粒子：合成-结构-性质关系和数据驱动的发现

• DOI: 10.1126/science.abn3103
• 发表时间: 2022
• 期刊: Science
• 影响因子: 56.9
• 作者: Yao, Yonggang;Dong, Qi;Brozena, Alexandra;Luo, Jian;Miao, Jianwei;Chi, Miaofang;Wang, Chao;Kevrekidis, Ioannis G.;Ren, Zhiyong Jason;Greeley, Jeffrey
• 通讯作者: Greeley, Jeffrey

Passive Oxide Film Growth Observed On the Atomic Scale

• DOI: 10.1002/admi.202102487
• 发表时间: 2022-02-26
• 期刊: ADVANCED MATERIALS INTERFACES
• 影响因子: 5.4
• 作者: Chen, Xiaobo;Liu, Zhenyu;Zhou, Guangwen
• 通讯作者: Zhou, Guangwen

Relation between cation distribution and chemical bonds in spinel NiFe2O4

尖晶石NiFe2O4中阳离子分布与化学键的关系

• DOI: 10.1016/j.mtcomm.2022.104436
• 发表时间: 2022
• 期刊: Materials Today Communications
• 影响因子: 3.8
• 作者: Fang, Ying;Zhang, Siming;Ohodnicki, Paul R.;Wang, Guofeng
• 通讯作者: Wang, Guofeng

Predicting mechanical properties of high entropy alloys with face centered cubic structure from first principles calculations

从第一原理计算预测面心立方结构高熵合金的机械性能

• DOI: 10.1016/j.mtcomm.2022.104059
• 发表时间: 2022
• 期刊: Materials Today Communications
• 影响因子: 3.8
• 作者: Zhang, Siming;Wang, Guofeng
• 通讯作者: Wang, Guofeng

Coupling between bulk thermal defects and surface segregation dynamics

体热缺陷与表面偏析动力学之间的耦合

• DOI: 10.1103/physrevb.104.085408
• 发表时间: 2021
• 期刊: Physical review
• 作者: J. Li, S. Zhang