Control of Kinetic Processes in Irradiated Alloys through Compositional Patterning

通过成分图案控制辐照合金的动力学过程

• 批准号: 0804615
• 负责人: Pascal Bellon
• 金额: $ 55.5万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0804615&HistoricalAwards=false
• 关键词: Control; Kinetic; Processes; Irradiated; Alloys

TECHNICAL: The advanced energy systems push operating environments to more severe and aggressive extremes, including high temperature, high radiation dose, and high mechanical stresses. A new generation of materials is required to meet these challenges since current materials, which were designed using knowledge developed as long as 50 years ago, will not operate safely, reliably, and economically under these conditions. This program explores a fundamentally new approach for the design of materials that would permanently resist radiation. PIs plan a new approach whereby alloy microstructures are designed to include a high density of point-defect traps that are dynamically stable under irradiation. This goal is achieved by taking advantage of PIs? past work on nanoscale compositional patterning induced by irradiation, and learning how to use these compositional heterogeneities as effective traps for point defects. By design, the nanostructured materials would thus be radiation-insensitive. PIs plan to apply this approach to selected Cu-base and Fe-base model alloys, as well as to similar alloys strengthened by nanoscale oxide dispersion. In the latter case, nanocomposite oxide-metal thin films are grown by combining cluster beam deposition with magnetron sputtering. The thin films are characterized before and after ion irradiation with a combination of techniques, including XRD, TEM, and atom probe tomography. A particular emphasis is put on the latter since it achieves sub-nanometric chemical resolution in three dimensions, and thus makes it possible to fully characterize nanostructured compositional patterns. The point-defect trapping efficiency of these nanostructures is assessed by radiation-enhanced diffusion and swelling measurements. A computational effort would identify the conditions for compositional patterns to remain dynamically stable even as the microstructure is slowly drifting. To achieve this goal, in collaboration with Lawrence Livermore National Laboratory, PIs will implement a new parallel kinetic Monte Carlo algorithm that speeds up simulations by several orders of magnitude, thus making it possible to follow the complex evolution of the microstructure in the simulations. NON-TECHNICAL: The research has broad scientific impact for the development of alloy design strategies for new materials that are critical to advanced energy production systems. Besides publishing widely the results from this research, PIs plan to organize, in the US, a summer school on Materials under Irradiation. The objective is to educate the next generation of scientists and engineers required to maintain or even expand the share of nuclear energy in the US energy production portfolio. In addition, the two graduate students working on this project will be trained on the most advanced instruments of materials characterization. PIs will hire undergraduate assistants, in particular women and underrepresented minorities. The present work will be integrated into the PIs teaching activities, exposing undergraduate students to the potentials and the challenges offered by nanostructured materials. PIs will also expand ?Materials Mobile? high-school visit program so as to reach a much larger student population.

技术：高级能源系统将操作环境推向更严重和更具侵略性的极端，包括高温，高辐射剂量和高机械应力。需要新一代材料来应对这些挑战，因为在50年前使用知识设计的当前材料将在这些条件下无法安全，可靠和经济地运作。该计划探讨了一种从根本上进行新的方法，用于设计将永久抵抗辐射的材料。 PIS计划了一种新的方法，该方法旨在将合金微结构设计为包括高密度的点缺失陷阱，这些陷阱在辐照下动态稳定。通过利用PI来实现此目标？过去的纳米级成分构图图案的工作是由辐照引起的，并学习如何使用这些组成异质性作为点缺陷的有效陷阱。通过设计，纳米结构的材料将不敏感。 PIS计划将这种方法应用于选定的Cu碱和Fe-碱模型合金，以及通过纳米氧化物分散体增强的类似合金。在后一种情况下，纳米复合氧化物 - 金属薄膜是通过将簇束沉积与磁控溅射结合在一起而生长的。薄膜在离子辐照之前和之后与包括XRD，TEM和Atom探针断层扫描在内的技术组合进行表征。由于它在三个维度上实现了亚纳米化学分辨率，因此特别强调了后者，因此可以充分表征纳米结构化的组成模式。通过辐射增强的扩散和肿胀测量来评估这些纳米结构的点陷阱捕获效率。计算工作将确定成分模式的条件，即使微观结构正在缓慢漂移，也可以动态稳定。为了实现这一目标，与Lawrence Livermore国家实验室合作，PIS将实施一种新的平行动力学蒙特卡洛算法，该算法将模拟加快了几个数量级，从而使模拟的复杂演化成为可能。非技术：这项研究对针对先进能源生产系统至关重要的新材料的合金设计策略的制定具有广泛的科学影响。除了广泛发布这项研究的结果外，PIS计划在美国组织一所暑期学校，以辐射。目的是教育下一代的科学家和工程师，以维持甚至扩大美国能源生产组合中核能的份额。此外，从事该项目的两位研究生将接受最先进的材料表征培训。 PI将雇用本科助理，尤其是妇女和代表性不足的少数民族。目前的工作将纳入PIS教学活动，使本科生面临纳米结构材料所面临的潜力和挑战。 PI也会扩展吗？材料移动？高中访问计划以达到更大的学生人数。