Unraveling the Fundamental Mechanisms of Nanoscale Deformation in Bulk Metallic Glasses

揭示块状金属玻璃纳米级变形的基本机制

• 批准号: 1901959
• 负责人: Udo Schwarz
• 金额: $ 65.72万
• 依托单位: Yale University
• 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 2022-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1901959&HistoricalAwards=false
• 关键词: Unraveling; Fundamental; Mechanisms; Nanoscale; Deformation

Although the lack of periodic atomic arrangements in bulk metallic glasses is responsible for multiple desirable properties such as high strength, superior elasticity, and an ability to be easily formed into virtually unlimited shapes, their disordered atomic structure and associated absence of defined shear planes also give rise to inferior room temperature ductility. As a result, the practical use of metallic glasses as structural materials is currently limited to only a few applications such as eyeglass frames, surgical tools, or golf clubs. In this award, experimental and theoretical approaches are combined to advance our knowledge of the atomic-scale processes governing the response of bulk metallic glasses to deformation. An improved understanding of microstructural damage mechanisms is a necessary pre-requisite to establish structure-property relationships that will allow custom-designed alloys to be produced with characteristics tailored to best match their intended applications. The students working on the project will have the unique opportunity to be trained in an area that combines interdisciplinary skills in micro- and nanomechanics, to perform investigations of materials at the scale of single atoms, to implement new experimental approaches, and to develop novel atomic scale molecular dynamics simulations. The research team will also engage with local schools to give lectures and demonstrations designed to encourage students to pursue careers in science and engineering.Metallic glasses accommodate plastic flow through the emergence of shear transformation zones, which are the smallest identifiable units in inhomogeneous plastic flow. If many such zones aggregate, shear bands can form that localize large shear strain inside a thin region of material. Such shear bands in metallic glasses are analogous to shear planes in crystals. Here, joint experimental and computational modeling studies are employed to investigate the initiation and growth of shear transformation zones, the shear bands they form, and the mechanical properties they control. Towards this end, nanoscale mechanical testing such as indentation and compression will be carried out on samples produced by innovative preparation methods to study how plastic flow is affected by strain rate, sample size, probing volume, and the structural properties of the material during deformation, the results of which will then be compared to computer simulations. This work seeks to develop an ability to quantitatively predict the initiation and propagation of shear bands, which is a critical step towards a mechanistic understanding of deformation and failure properties as well as identifying ductility and toughness enhancement methods for metallic glasses.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.

尽管在大块金属玻璃中缺乏周期性原子排列是许多理想性能的原因，如高强度，优越的弹性，以及容易形成几乎无限形状的能力，但它们无序的原子结构和相关的定义剪切面的缺乏也导致了较差的室温延展性。因此，金属玻璃作为结构材料的实际应用目前仅限于少数应用，如眼镜框架，手术工具或高尔夫球杆。在这个奖项中，实验和理论方法相结合，以推进我们对控制大块金属玻璃变形响应的原子尺度过程的认识。提高对微观结构损伤机制的理解是建立结构-性能关系的必要先决条件，这将使定制设计的合金能够生产出具有最适合其预期应用的特性的合金。参与该项目的学生将有独特的机会在微观和纳米力学的跨学科技能领域接受培训，在单原子尺度上对材料进行研究，实施新的实验方法，并开发新的原子尺度分子动力学模拟。研究小组还将与当地学校合作，举办讲座和示范活动，鼓励学生从事科学和工程方面的职业。金属玻璃通过出现剪切转变区来容纳塑性流动，剪切转变区是非均匀塑性流动中最小的可识别单元。如果许多这样的区域聚集在一起，可以形成剪切带，在材料的薄区域内局部产生大的剪切应变。金属玻璃中的这种剪切带类似于晶体中的剪切面。本文采用实验和计算模型相结合的方法，研究了剪切转变带的形成和发展、剪切带形成的剪切带及其控制的力学性能。为此，将对采用创新制备方法生产的样品进行纳米级机械测试，如压痕和压缩，以研究变形过程中塑性流动如何受到应变速率、样品尺寸、探测体积和材料结构特性的影响，然后将其结果与计算机模拟进行比较。这项工作旨在发展定量预测剪切带的开始和扩展的能力，这是对变形和破坏特性的机理理解以及确定金属玻璃的延展性和韧性增强方法的关键一步。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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

Angstrom-scale replication of surfaces with crystallized bulk metallic glasses

• DOI: 10.1016/j.mtnano.2021.100145
• 发表时间: 2021-10-24
• 期刊: MATERIALS TODAY NANO
• 影响因子: 10.3
• 作者: Chen，Z.;Xie，Y.;Schwarz，U. D.
• 通讯作者: Schwarz，U. D.

Atomic-scale homogeneous plastic flow beyond near-theoretical yield stress in a metallic glass

• DOI: 10.1038/s43246-021-00124-3
• 发表时间: 2021-02
• 期刊: Communications Materials
• 影响因子: 7.8
• 作者: Jiaxin Yu;A. Datye;Zheng Chen;Chao Zhou;Omur E. Dagdeviren;J. Schroers;U. Schwarz

Relaxation and crystallization studied by observing the surface morphology evolution of atomically flat Pt57.5Cu14.7Ni5.3P22.5 upon annealing

• DOI: 10.1016/j.scriptamat.2020.02.035
• 发表时间: 2020-06
• 期刊: Scripta Materialia
• 影响因子: 6
• 作者: Zheng Chen;A. Datye;Jittisa Ketkaew;S. Sohn;Chao Zhou;Omur E. Dagdeviren;J. Schroers;U. Schwarz

Atomic-Scale Imprinting by Sputter Deposition of Amorphous Metallic Films

非晶金属薄膜溅射沉积的原子级压印

• DOI: 10.1021/acsami.0c14982
• 发表时间: 2020
• 期刊: ACS Applied Materials & Interfaces
• 影响因子: 9.5
• 作者: Chen, Zheng;Datye, Amit;Simon, Georg H.;Zhou, Chao;Kube, Sebastian A.;Liu, Naijia;Liu, Jingbei;Schroers, Jan;Schwarz, Udo D.
• 通讯作者: Schwarz, Udo D.

Atomic imprinting in the absence of an intrinsic length scale

• DOI: 10.1063/5.0027982
• 发表时间: 2020-11
• 期刊: APL Materials
• 影响因子: 6.1
• 作者: Chao Zhou;A. Datye;Zheng Chen;G. Simon;Xinzhe Wang;J. Schroers;U. Schwarz