NSF-EC Cooperative Activity in Computational Materials Research: Modeling Microstructural Evolution with Digital Materials

这一奖项是对材料世界网提交的关于NSF和EC之间的计算材料合作研究的建议的回应。卡内基梅隆大学(CMU)和普林斯顿大学提议与欧洲的三个机构合作，解决再结晶建模的多尺度挑战。该项目的美方将解决材料的三维表示问题，包括微观结构和状态的相关方面，导致形核的异质亚晶粗化，恢复过程中的位错动力学，以及与微观结构演变相关的晶界特性。例如，水平集方法的最新发展开辟了新的可能性，并将使我们能够对恢复过程中发生的复杂的位错运动进行定量预测，包括爬升和滑行。在一个稍粗的尺度上，亚晶粗化的模型和理论已经发展到应该应用于在变形材料中观察到的复杂和可变结构的点上。因此，该项目将对材料的基础研究产生具体影响，因为它将通过定量的预测模型对微观结构演变过程产生新的理解。它还将通过对定期进行国际交流的学生进行教育，并通过开发可随时转移到工业界用于模拟商品材料加工的工具，产生广泛的影响。合作的总体主旨是开发数字微结构方法，该方法将开发计算工具，通过从边界运动所需的原子尺度的数值表征和模拟，从变形的位错动力学随后在晶胞和亚晶尺度上的恢复，到塑性变形的晶粒度方面，再加上边界的长期运动(作为再结晶前沿)，来处理非均匀塑性变形与回复和再结晶过程的组合。该团队的美国成员将专注于关键方面，如晶界的动力学性质(流动性)、恢复过程中的位错动力学以及再结晶过程的介观模拟，包括所有相关特征，如晶体结构和晶体取向。将通过将计算出的微结构的统计数据与实验测量的微结构进行比较(根据先前工作提供的数据)，对这套计算工具的预测能力进行验证。这份提案概述了整个合作项目，但只详细描述了那些将在美国开展的方面。确定了将在美国实施的计划的要素。*

This award is being made in response to a proposal submitted under the Materials World Net for collaborative research on computational materials between the NSF and EC. Carnegie Mellon University (CMU) and Princeton University propose to team with three institutions in Europe to address the multiscale challenges of modeling recrystallization. The US side of the project will address issues of three-dimensional representation of materials that include the relevant aspects of microstructure and state, heterogeneous subgrain coarsening leading to nucleation, dislocation dynamics during recovery and grain boundary properties relevant to microstructural evolution. Recent developments in level set methods, for example, have opened up new possibilities and will allow us to make quantitative predictions of the complex dislocation motions that occur during recovery that include climb as well as glide. At a somewhat coarser length scale, modeling and theory of subgrain coarsening has progressed to the point where it should be applied to the complex and variable structures observed in deformed materials. Thus the project will have specific impact on fundamental research on materials in terms of developing new understanding of the processes of microstructural evolution via quantitative, predictive models. It will also have broad impact through the education of students with regular international exchanges and through the development of tools that can be readily transferred to industry for modeling the processing of commodity materials. The overall thrust of the collaboration is to develop the Digital Microstructures approach that will develop computational tools that address the combination of heterogeneous plastic deformation with recovery and recrystallization processes through numerical characterization and simulation from the atomistic scale required for boundary motion, through dislocation dynamics of deformation followed by recovery at the cell and subgrain scale, to the grain-scale aspects of plastic deformation, coupled with long-range motion of boundaries (as recrystallization fronts). The US members of the team will concentrate on key aspects such as kinetic properties of grain boundaries (mobility), dislocation dynamics in recovery and mesoscopic simulation of the recrystallization process including all relevant features such as grain structure and crystallographic orientation. Verification of the predictive capability of the set of computational tools will be conducted by comparing the statistics of the computed microstructures to microstructures measured experimentally (based on data available from prior work). This proposal outlines the entire collaborative project but only those aspects to be worked on in the US are described in full. The elements of the program to be conducted in the US are identified.***