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.

技术支持：先进的能源系统将操作环境推向更严峻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，因为使用50年前开发的知识设计的现有材料在这些条件下无法安全，可靠和经济地运行。该计划探索了一种从根本上设计永久抗辐射材料的新方法。PI计划一种新的方法，合金微结构的设计，包括一个高密度的点缺陷陷阱，在辐照下动态稳定。这一目标是通过利用PI实现的？过去的工作纳米组成图案诱导辐射，并学习如何使用这些组成的异质性作为有效的陷阱点缺陷。通过设计，纳米结构材料因此将是辐射不敏感的。PI计划将这种方法应用于选定的铜基和铁基模型合金，以及通过纳米氧化物分散强化的类似合金。在后一种情况下，纳米复合氧化物-金属薄膜的生长通过结合团簇束沉积与磁控溅射。薄膜的特征在于之前和之后的离子辐照与技术的组合，包括XRD，TEM，和原子探针断层扫描。特别强调的是后者，因为它实现了亚纳米级的化学分辨率在三个维度上，从而使其能够充分表征纳米结构的组成图案。这些纳米结构的点缺陷捕获效率通过辐射增强扩散和溶胀测量进行评估。计算工作将确定组成模式保持动态稳定的条件，即使微观结构缓慢漂移。为了实现这一目标，PI将与劳伦斯利弗莫尔国家实验室合作，实施一种新的并行动力学蒙特卡罗算法，将模拟速度提高几个数量级，从而使模拟中微观结构的复杂演变成为可能。非技术性：该研究对开发对先进能源生产系统至关重要的新材料的合金设计策略具有广泛的科学影响。除了广泛发表这项研究的结果外，PI还计划在美国组织一个关于辐照材料的暑期学校。其目标是教育下一代科学家和工程师，以保持甚至扩大核能在美国能源生产组合中的份额。此外，该项目的两名研究生将接受最先进的材料表征仪器的培训。PI将雇用本科生助理，特别是女性和代表性不足的少数民族。目前的工作将被整合到PI的教学活动中，使本科生接触到纳米结构材料所带来的潜力和挑战。PI也将扩大？材料移动的？高中访问计划，以便接触更多的学生。