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.

尽管散装金属眼镜中缺乏周期性的原子布置负责多种理想的特性，例如高强度，出色的弹性以及几乎无限的形状，但其无序的原子结构和相关的剪切平面的缺乏也会提高室温下的室温下。结果，将金属眼镜作为结构材料的实际使用仅限于少数几个应用，例如眼镜框架，外科手术工具或高尔夫球俱乐部。在该奖项中，结合了实验和理论方法，以促进我们对批量金属眼镜对变形的响应的原子规模过程的了解。对微观结构损害机制的改进理解是建立结构性关系关系的必要前提条件，这将允许定制设计的合金具有量身定制的特征，以最佳地匹配其预期的应用。从事该项目的学生将有独特的机会在结合微力学和纳米力学的跨学科技能的领域进行培训，以单个原子的规模对材料进行研究，以实施新的实验方法，并开发新的原子量表分子动力学模拟。研究团队还将与当地学校互动，进行讲座和示威活动，旨在鼓励学生从事科学和工程领域的职业。金色的眼镜可以通过剪切转换区的出现来容纳塑料流，这是不均匀塑料流中最小的可识别单元。如果许多这样的区域聚集，剪切带可以形成将大剪切应变定位在薄的材料区域内。金属眼镜中的这种剪切带类似于晶体中的剪切平面。在这里，采用了联合实验和计算建模研究来研究剪切转化区，它们形成的剪切带及其控制的机械性能的启动和生长。为此，将对通过创新制备方法产生的样品进行纳米级机械测试，例如研究塑料流量如何受应变速率，样本量，探测体积和变形过程中材料的结构特性的影响，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启动和传播的能力，这是迈向对变形和故障属性的机械理解的关键一步，并确定金属眼镜的延展性和韧性增强方法。该奖项反映了NSF的法定任务，并通过评估了基金会的范围，并通过评估了基金会的范围。

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.

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 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

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

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.