EAGER: IMPRESS-U: Gradient surface nanostructuring with short laser pulses

EAGER：IMPRESS-U：使用短激光脉冲进行梯度表面纳米结构

• 批准号: 2406599
• 负责人: Leonid Zhigilei
• 金额: $ 29.79万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-03-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2406599&HistoricalAwards=false
• 关键词: EAGER; IMPRESS; Gradient; surface; nanostructuring

The rapidly growing industrial demand for high-performance materials exhibiting a combination of high strength and hardness, substantial ductility, and fatigue resistance has been driving the development of so called “nanostructured materials,” where a high density of crystal defects (grain boundaries, twins, stacking faults and dislocations) can lead to a striking enhancement of the mechanical properties. The utilization of nanostructured materials, however, is limited by their poor thermal stability against grain coarsening and defect annihilation, as well as difficulties of the scale-up of existing synthesis techniques and their integration into modern manufacturing processes. This EArly-concept Grant for Exploratory Research (EAGER) International Multilateral Partnerships for Resilient Education and Science System in Ukraine (IMPRESS-U) award supports the exploration of a novel non-contact approach to surface nanostructuring based on a simultaneous generation of a high density of crystal defects by short pulse laser processing and stabilization of these defects through the laser-assisted nanoalloying. The goal of this project is to provide a proof of concept for the feasibility of a nimble laser-assisted defect engineering and stabilization, pushing forward the frontiers of the laser processing technologies. The project benefits from the complementary expertise and existing research links between the members of the international research team from the United States, Lithuania, and Ukraine. One of the major goals of the project is to establish a long-term sustainable collaboration fully integrating Ukrainian researchers into the global research community. Mutual visits, exchange of research expertise, and educational activities create a fertile ground for the emergence of a new area of research strength at the Lviv Polytechnic National University. In particular, the best practices of a well-established Center of Laser Technologies in Vilnius, Lithuania are adopted by the research center emerging at Lviv Polytechnic. Leveraging computational expertise at the University of Virginia grounds investigations at the Ukrainian research center on solid fundamental understanding of processes underlying material modifications from short pulse laser processing.The challenge of revealing and untangling the intertwined processes responsible for the generation of various crystal defects in laser nanostructuring is addressed in this project by combining large-scale atomistic modeling of laser-induced structural and phase transformations, advanced large-area non-ablative laser processing using a novel setup for nanoalloying, and nanoscale characterization of the laser-modified surfaces. The stabilization of laser-generated highly nonequilibrium defect structures through nanoalloying is achieved by adding alloying elements that preferentially segregate to grain boundaries and other defects, thus reducing the free energy of nanocrystalline structures and acting as obstacles for defect migration. The fundamental mechanisms responsible for the generation of crystal defects at a rapidly advancing crystallization front and their stabilization through nanoalloying is systematically investigated in atomistic simulations. The conditions of the simulations are mapped to those realized in laser processing, and the computational predictions are verified in a detailed experimental characterization of surface regions modified by short pulse laser irradiation. The direct mapping of the computational predictions to the results of nanoscale characterization of laser modified surfaces guides the exploration of the multidimensional space of laser processing parameters and enables the verification and refinement of the model assumptions. Several strategies for expanding the range of irradiation conditions leading to nanocrystallization are explored, including suppression of subsurface cavitation and spallation by performing laser processing in a liquid environment and under confinement by a transparent solid overlayer. The effect of alloying/compositional gradients on the solidification kinetics and final nanostructure are systematically investigated for different target configurations in simulations and experiments.This EAGER: IMPRESS-U project is jointly funded by NSF, Research Council of Lithuania, US National Academies of Sciences, and Office of Naval Research Global (DoD). US portion of this collaborative partnership project is supported by NSF Office of International Science and Engineering (Office of the Director), CMMI’s Advanced Manufacturing Program (Engineering Directorate), and DMR’s Metals and Metallic Nanostructures Program (Directorate for Mathematical and Physical Sciences).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

对具有高强度和硬度、高延展性和抗疲劳性的高性能材料的快速增长的工业需求一直在推动所谓“纳米结构材料”的发展，其中高密度的晶体缺陷（晶界、孪晶） ，堆垛层错和位错）可以导致机械性能的显着提高，然而，纳米结构材料的使用受到其对晶粒粗化和缺陷消除的热稳定性差以及放大困难的限制。这项早期概念探索性研究资助 (EAGER) 乌克兰弹性教育和科学系统国际多边合作伙伴关系 (IMPRESS-U) 奖项支持探索一种新颖的非接触式方法。该项目的目标是通过短脉冲激光加工同时生成高密度晶体缺陷，并通过激光辅助纳米合金化稳定这些缺陷，从而实现表面纳米结构。灵活的激光辅助缺陷工程和稳定的可行性，推动激光加工技术的前沿发展 该项目受益于来自美国、立陶宛和乌克兰的国际研究团队成员之间的互补专业知识和现有研究联系。该项目的主要目标之一是建立长期可持续的合作关系，将乌克兰研究人员充分融入全球研究界，相互访问、交流研究专业知识和教育活动为新领域的出现创造肥沃的土壤。的研究实力特别是，利沃夫理工学院新兴的研究中心采用了立陶宛维尔纽斯成熟的激光技术中心的最佳实践，利用了乌克兰研究中心的弗吉尼亚大学的计算专业知识。对短脉冲激光加工材料改性过程的坚实基础理解。该项目通过结合大规模激光加工技术，解决了揭示和理清导致激光纳米结构中各种晶体缺陷产生的相互交织的过程的挑战激光诱导结构和相变的原子建模、使用新型纳米合金化装置的先进大面积非烧蚀激光加工以及激光改性表面的纳米级表征通过纳米合金化来稳定激光产生的高度非平衡缺陷结构。这是通过添加优先偏析到晶界和其他缺陷的合金元素来实现的，从而降低了纳米晶体结构的自由能并充当缺陷迁移的障碍。在原子模拟中系统地研究了快速前进的结晶前沿晶体缺陷的产生及其通过纳米合金化的稳定性，将模拟条件映射到激光加工中实现的条件，并在表面区域的详细实验表征中验证了计算预测。通过短脉冲激光照射进行改性，将计算预测直接映射到激光改性表面的纳米级表征结果，指导了对激光加工参数的多维空间的探索，并能够验证和细化模型。探索了扩大导致纳米结晶的照射条件范围的几种策略，包括通过在液体环境中和在透明固体覆盖层的限制下进行激光加工来抑制表面下空化和散裂。在模拟和实验中系统地研究了不同目标配置的凝固动力学和最终纳米结构。这个EAGER：IMPRESS-U项目由美国国家科学基金会、美国国家科学基金会研究委员会共同资助该合作伙伴关系项目的美国部分由立陶宛、美国国家科学院和全球海军研究办公室 (DoD) 得到 NSF 国际科学与工程办公室（主任办公室）、CMMI 先进制造计划（工程理事会）的支持。 ，以及 DMR 的金属和金属纳米结构计划（数学和物理科学理事会）。该奖项反映了 NSF 的法定使命，并通过使用基金会的评估进行评估，被认为值得支持智力价值和更广泛的影响审查标准。