Multi-scale Modeling of Deformation in Nanostructured Metallic Systems

纳米金属代表着一类高强度的工程材料，对电子、航空航天和汽车工业都有好处。然而，由于它们的热稳定性和缺乏延展性，它们的应用一直受到限制。已经开发出一种通过热机械处理来解决这些限制的策略。该奖项支持基础研究，以了解通过这种加工提高纳米晶金属延展性的机制。这项研究将使可持续的块状纳米结构金属的开发具有高强度和延展性，以承受在高温和压力等极端环境中的应用。这项工作还将为本科生和研究生提供培训，以满足未来计算驱动材料开发的需求。该奖项支持的研究的目标是发展对晶界面貌工程纳米晶体金属中的合作和竞争变形机制的基本理解。它将阐明它们对力学性能的分级贡献，并建立它们与晶界面色的无序状态之间的联系。该项目将开发多尺度建模方法，借鉴原子、介观动力学和连续介质力学模拟，利用动力学蒙特卡罗算法和有限元方法来连接时间和长度尺度。该模型与现场中子衍射测量的直接联系将严格确定形变与晶界结构演化的动态相互作用。该项目的发现有望促进当前对这些材料中控制行为的潜在机制的了解，并告知它们在复杂的非平衡金属结构中的耦合。研究结果将为机械增强纳米结构金属体系的配位工程设计提供指导。

Nanocrystalline metals represent a class of high-strength engineering materials with benefits for the electronics, aerospace, and automotive industries. However, their applications have been limited by their thermal instability and a lack of ductility. A strategy to address these limitations through thermo-mechanical treatment has been developed. This award supports fundamental research to understand the mechanisms that lead to improved ductility in nanocrystalline metals through this processing. The research will enable the development of sustainable bulk nanostructured metals with high strength and ductility to withstand application in extreme environments such as high temperatures and stresses. The work will also provide training to undergraduate and graduate students to meet the future needs of computationally-driven materials development.The goal of the research supported by this award is to develop fundamental understanding of the cooperating and competing deformation mechanisms in grain boundary complexion-engineered nanocrystalline metals. It will elucidate their hierarchical contributions to mechanical performance and establish their connection with the disordered state of grain boundary complexion. This project will develop multi-scale modeling approaches, drawing from atomistic, mesoscale dynamics, and continuum mechanics simulations, utilizing kinetic Monte Carlo algorithm and finite element methods to bridge time and length scales. The direct connection of the model with in-situ neutron diffraction measurements will rigorously determine the dynamical interplay of deformation and grain boundary structural evolution. The findings of this project are expected to advance current knowledge of the underlying mechanisms controlling behavior in these materials, and to inform their coupling in the complex non-equilibrium metallic structures. The research results will provide guidance to complexion engineering for the design of mechanically-enhanced nanostructured metallic systems.