权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Resolving Twin-Slip Interaction Mechanisms in Hexagonal Close-Packed Metals

解决六方密排金属中的双滑移相互作用机制

基本信息

批准号：
2016263
负责人：
Yantao Shen
金额：
$ 26.87万
依托单位：
Board of Regents, NSHE, obo University of Nevada, Reno
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：
2020-08-01 至 2024-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2016263&HistoricalAwards=false
关键词：
Resolving Twin Slip Interaction Mechanisms

项目摘要

Deformation of hexagonal close-packed metals, such as magnesium and titanium, involves complex activities of defects in the crystal structure, called twins and dislocations, respectively. Multiple modes of twinning and dislocation slip in crystal planes can be activated, even under simple mechanical loading. Interaction between twin boundaries and dislocations strongly influences the mechanical properties of these metals, but the physics behind the interaction is not understood. This award supports fundamental research on modeling the twin-slip interaction mechanisms, which are difficult to be resolved experimentally. The research will enhance fundamental understanding of the mechanical behavior of important engineering materials, such as magnesium and titanium alloys, that have shown promise in improving energy efficiency in automotive and aerospace applications. Insights obtained from the research will also help design new generation of lightweight alloys with improved strength and ductility. Additionally, the project will promote education and diversity by facilitating integrated computational materials engineering education for undergraduate and graduate students and by engaging underrepresented groups in STEM activities.Twin-slip interaction in metals with hexagonal close-packed crystal structures plays a crucial role in the mechanical properties of these materials. Such interaction has been considered an important factor in the hardening behavior during plastic deformation, but the mechanisms remain largely unknown. Twin-slip interaction occurs on the atomic scale. According to classical theory of deformation twinning, a one-to-one lattice correspondence exists between the parent and the product phase. Thus, if a dislocation in the matrix is transformed into a dislocation in the twin, the slip planes before and after twin-slip interaction must be corresponding planes. These corresponding planes can be unambiguously identified with atomistic simulations. The project will use atomic scale simulations to resolve lattice transformations during interaction between various twinning modes and dislocation modes in magnesium and titanium. By analyzing lattice correspondence, the interaction mechanisms can be resolved with clarity. Conditions for dislocation transmutation and dislocation absorption at different twin boundaries can also definitively be established. And the results obtained can be further extended to other important engineering metals such as zirconium and cobalt alloys.This project is jointly supported by the Civil, Mechanical and Manufacturing Innovations Division in the Engineering Directorate, and the Division of Materials Research in the Mathematical and Physical Sciences Directorate.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.

六方密排金属（如镁和钛）的变形涉及晶体结构中缺陷的复杂活动，分别称为孪晶和位错。即使在简单的机械载荷下，也可以激活晶面中的多种孪晶和位错滑移模式。孪晶界和位错之间的相互作用强烈影响这些金属的机械性能，但相互作用背后的物理机制尚不清楚。该奖项支持对双滑移相互作用机制进行建模的基础研究，这些机制很难通过实验解决。该研究将增强对镁和钛合金等重要工程材料机械行为的基本理解，这些材料在提高汽车和航空航天应用的能源效率方面表现出了希望。从研究中获得的见解也将有助于设计具有更高强度和延展性的新一代轻质合金。此外，该项目还将通过促进本科生和研究生的综合计算材料工程教育，以及让代表性不足的群体参与STEM活动，促进教育和多样性。具有六方密排晶体结构的金属中的双滑移相互作用在这些材料的机械性能中起着至关重要的作用。这种相互作用被认为是塑性变形过程中硬化行为的一个重要因素，但其机制在很大程度上仍然未知。双滑移相互作用发生在原子尺度上。根据变形孪晶的经典理论，在母体相和产物相之间存在一对一的晶格对应。因此，如果基体中的位错转化为孪晶中的位错，则孪晶滑移相互作用前后的滑移面必须是对应的面。这些对应的平面可以用原子模拟明确地识别。该项目将使用原子尺度模拟来解决镁和钛中各种孪生模式和位错模式之间相互作用期间的晶格转变。通过分析晶格对应，可以清楚地解决相互作用机制。还可以明确地建立在不同孪晶界处位错嬗变和吸收的条件。并且所获得的结果可以进一步扩展到其他重要的工程金属，如锆和钴合金。该项目由工程理事会的土木，机械和制造创新部门共同支持，该奖项反映了NSF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。