NSF/Sandia: Collaborative Research: Adaptive Hierarchical Multiscale Framework for Modeling the Deformation of Ultra-Strong Nano-Structured Materials

摘要纳米结构材料对于要求高强度和高延展性的应用具有极大的吸引力。其中两个领域是：（1）用于要求高强度重量比的未来航空航天应用的纳米层状复合材料;以及（2）未来几代电子设备中的下一代互连和封装组件。虽然原子分子动力学（MD）模拟是研究纳米尺度变形现象的最可靠的工具（在没有电子结构考虑的情况下），但它们仅限于非常小的体积和短的模拟时间。同样，位错动力学模拟的能力有限，以解决核心结构的缺陷，并将位错成核事件没有特设的假设。我们计划开发一个自适应分层多尺度框架（AHMF），其中适当的规模和物理模型误差估计的基础上自适应地选择。利用这个框架，我们计划研究两类纳米结构材料的变形特性：多晶纳米孪晶铜互连和多层纳米复合材料。我们将应用这些新工具来设计bcc/fcc奈米层状材料，以及发展具有超高强度和正常导电率的奈米孪晶铜互连线，使其可作为独立式互连线

Abstract Nano-structured materials are extremely attractive for applications requiring high strength and ductility. Two such areas are: (1) nano-layered composites for future aerospace applications demanding high strength-to-weight ratios; and (2) next-generation interconnect and packaging components in future generations of electronic devices. While atomistic Molecular Dynamics (MD) simulations are the most reliable tools for investigating deformation phenomena at the nano-scale (in absence of electronic structure considerations), they are limited to very small volumes and short simulation times. Likewise, dislocation dynamics simulations are limited in the ability to resolve the core structure of defects and to incorporate dislocation nucleation events without ad hoc assumptions. We plan to develop an adaptive hierarchical multiscale framework (AHMF) , where appropriate scale and physics are selected adaptively based on model error estimators.. Using this framework, we plan to investigate the deformation characteristics of two classes of nano-structured materials: polycrystalline nano-twinned copper inter-connects, and multi-layer nano-composites. We will apply these new tools to the design of bcc/fcc nano-layered materials, and the development of nano-twinned Cu interconnect lines with ultra-high strength and normal conductivity so that they can act as free standing interconnects