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.

六角形封闭式金属（例如镁和钛）的变形分别涉及晶体结构中缺陷的复杂活性，分别称为双胞胎和脱位。即使在简单的机械载荷下，也可以激活多种晶体平面中的双重和脱位模式。双边界和位错之间的相互作用强烈影响这些金属的机械性能，但是相互作用背后的物理学尚不清楚。该奖项支持建模双滑移相互作用机制的基础研究，这些机制很难通过实验解决。这项研究将增强对重要工程材料（例如镁和钛合金）机械行为的基本理解，这表明在提高汽车和航空航天应用的能源效率方面有望。从研究中获得的见解还将有助于设计新一代的轻质合金，以提高强度和延展性。此外，该项目将通过促进本科和研究生的综合计算材料工程教育来促进教育和多样性，并通过使代表性不足的群体参与STEM活动。Twin-SLIP相互作用具有六角形封闭式填充的晶体结构在这些材料机械特性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重要因素，但这些机制在很大程度上未知。双滑移相互作用发生在原子量表上。根据经典的变形孪生理论，父母和产品阶段之间存在一对一的晶格对应关系。因此，如果将基质中的脱位转换为双胞胎中的位错，则在双滑动相互作用之前和之后的滑动平面必须是相应的平面。这些相应的平面可以通过原子模拟明确识别。该项目将使用原子量表模拟在镁和钛中的各种双胞胎模式和位错模式之间的相互作用期间解决晶格变换。通过分析晶格对应关系，可以清楚地解决相互作用机制。在不同双边界处的脱位变异和脱位吸收条件也可以确定确定。并且获得的结果可以进一步扩展到其他重要的工程金属，例如锆和钴合金。该项目得到了工程局的民用，机械和制造创新部的共同支持，以及数学和物理科学局的材料研究部以及该奖项的材料研究部。这些奖项反映了NSF的合法传教士和范围的均具有良好的影响。标准。