Collaborative Research: Novel Atomistic-Continuum Simulation of Sequential Grain Boundary-Dislocation Slip Transfer Reactions

合作研究：连续晶界位错滑移传递反应的新型原子连续模拟

• 批准号: 1233113
• 负责人: Youping Chen
• 金额: $ 14.07万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1233113&HistoricalAwards=false
• 关键词: Collaborative; Research; Novel; Atomistic; Continuum

The research objective of this award is to advance a coupled atomistic-continuum simulation method to explore slip transfer at grain boundaries. Lack of such a method is a current obstacle to progress towards developing constitutive relations that reflect the structure and behavior of grain boundaries, for example in polycrystal plasticity. The problem is complicated by the need to account for long range interactions of dislocation fields while also considering the atomic-level structural detail of the interface. This research will explore processes of sequential dislocation reactions with bicrystal interfaces by maintaining full atomistic resolution of the interface reactions and successively coarse graining the field description away from the interfaces at distances that are normally inaccessible to fully resolved molecular dynamics. Such a capability will enable parametric studies of dislocation-grain boundary slip transfer reactions over the full range of grain boundary degrees of freedom, including tilt and twist boundaries, as well as asymmetric boundaries that often have faceted structure and can give rise to profuse dislocation nucleation. Nanotwinned structures with a wide range of twin spacing will also be considered. This work will use state-of-the-art embedded atom method potentials which have proven quite accurate for fcc metals such as Cu in modeling various aspects of dislocation nucleation, formation of stacking faults, and dislocation interactions This research will advance a computational method that couples fully atomistic descriptions of nanoscale metallic behavior to mesoscale and macroscale constitutive behavior. It will permit study of the complex interactions that occur between dislocations and grain boundaries in polycrystalline metals which will lead to physics-based predictive constitutive models for metals. This research will advance the multiscale modeling of metals and lead to improved simulation and ultimately design of materials. Results of the research will be incorporated into graduate courses at both institutions.

该奖项的研究目标是推进耦合原子连续模拟方法来探索晶界处的滑移传递。缺乏这种方法是当前发展反映晶界结构和行为的本构关系（例如多晶塑性）方面取得进展的障碍。由于需要考虑位错场的长程相互作用，同时还要考虑界面的原子级结构细节，问题变得更加复杂。 这项研究将通过保持界面反应的完全原子分辨率，并在通常无法完全解析分子动力学的距离处连续粗粒化远离界面的场描述，来探索双晶界面的顺序位错反应的过程。这种能力将使位错-晶界滑移转移反应在整个晶界自由度范围内进行参数化研究，包括倾斜和扭曲边界，以及通常具有多面结构并可能引起大量位错成核的不对称边界。还将考虑具有宽范围孪晶间距的纳米孪晶结构。这项工作将使用最先进的嵌入式原子方法势，该势已被证明对于 Cu 等面心立方金属在位错成核、堆垛层错的形成和位错相互作用的各个方面的建模非常准确。这项研究将推进一种计算方法，将纳米级金属行为的完全原子描述与介观和宏观本构行为结合起来。它将允许研究多晶金属中位错和晶界之间发生的复杂相互作用，这将导致基于物理的金属预测本构模型。这项研究将推进金属的多尺度建模，并改进模拟和最终的材料设计。研究结果将纳入两个机构的研究生课程。