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: 1232878
• 负责人: David McDowell
• 金额: $ 24.62万
• 依托单位: Georgia Tech Research Corporation
• 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=1232878&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一种耦合的原子 - 孔子模拟方法，以探索晶界的滑移转移。缺乏这种方法是发展构成关系的当前障碍，该关系反映了晶界的结构和行为，例如在多晶可塑性中。由于需要考虑脱位场的远距离相互作用，同时还考虑了界面的原子级结构细节，因此问题使问题变得复杂。 这项研究将通过维持界面反应的完全原子分辨率，并依次将场描述从距离界面上的完全分解，从通常无法访问以完全分辨的分子动力学来探索与双晶界面的顺序脱位反应的过程。这种能力将在整个晶粒边界的自由度（包括倾斜和扭曲边界）以及通常具有刻面结构的不对称边界上的整个晶粒边界范围内进行脱位晶粒边界滑移反应的参数研究，并可能引起大量的脱位成核。还将考虑具有宽范围的双间距的纳米温构结构。这项工作将使用最新的嵌入原子方法电位，事实证明，对于FCC金属（例如CU），例如CU在建模位错成核的各个方面，堆叠故障的形成和脱位相互作用时，这项研究将推进一种计算方法，该方法将推进一种对纳米级金属行为对纳米级金属行为的态度的态度，以使金属级别的行为和米斯科构成均可构成。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，这将导致基于物理学的金属预测本构模型。这项研究将推进金属的多尺度建模，并导致改进的仿真并最终设计材料。研究结果将纳入两个机构的研究生课程中。