NSF-BSF: Stress-Assisted Structural Phase Transformations and Plasticity in Bicontinuous Nanomaterials

NSF-BSF：双连续纳米材料中的应力辅助结构相变和塑性

• 批准号: 2208681
• 负责人: Niaz Abdolrahim
• 金额: $ 28.74万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2208681&HistoricalAwards=false
• 关键词: NSF; BSF; Stress; Assisted; Structural

Nanoporous (NP) metals with tortuous surfaces and large surface-to-volume ratio are promising candidates for various important advanced technologies, from electrochemical sensors/actuators and fuel cell filters to energy conversion and storage systems. However, a hindrance to widespread technological application of NP metals is that they fail suddenly and with minimal uniform macroscopic plastic deformation. This award supports fundamental research to explore new ways of enabling homogeneous deformation in bicontinuous NP materials via alternative phase transformation (PT) mechanisms. The homogenous PT mechanisms would prevent localized deformation and, thus, enhance ductility across the whole system. The insights to be gained in this project will enable design of strong and ductile NP materials by utilizing metastable phases which cannot be obtained in conventional bulk metals and alloys. The fundamental mechanisms elucidated in this project will be applicable to other refractory materials and can also be scaled up for large-scale structural and functional applications. The award will also support undergraduate summer internships, a workshop on exploring nanotechnology for high school students with focus on underrepresented minority participation, and international student exchange.This project seeks to enable mechanisms of uniform (instead of local) PT and achieve significantly improved plastic deformability in Molybdenum (Mo)-based NP metals. Extreme stresses (on the order of tens of gigapascals) are required to thermodynamically drive a PT in Mo from a low-energy body centered cubic phase to a high-energy face centered cubic state instead of activating dislocation nucleation or propagation mechanisms. While this PT has been observed locally and at the atomic scale, it remains totally unclear whether it can occur homogenously to significantly modify mechanical behavior of specimens larger than about hundred nanometers in size. This project will study the combination of microstructure features including 1) small (defect-free) ligaments, 2) tortuosity of the structure, and 3) interfaces between Mo and a secondary material, that will enable a uniform distribution of high internal stresses through the entirety of NP composite structures and promote uniform deformation and better ductility. Molecular dynamics simulations and nanomechanical testing experiments with finite elements analysis will be integrated to study the mechanical response and post mortem microstructures for potential PT-based uniform plastic deformation.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.

纳米多孔（NP）金属具有曲折表面和较大的地表与体积比率是各种重要高级技术的有前途的候选者，从电化学传感器/执行器和燃料电池过滤器到能量转换和存储系统。但是，NP金属的广泛技术应用的障碍是，它们突然失败，并且宏观宏观塑性变形最小。该奖项支持基本研究，以探索通过替代相变（PT）机制在双连续NP材料中实现均质变形的新方法。同质PT机制将防止局部变形，从而增强整个系统的延展性。在该项目中获得的见解将通过利用亚稳态相，可以在常规的散装金属和合金中获得强大的NP材料设计。该项目中阐明的基本机制将适用于其他难治材料，也可以扩大规模用于大规模的结构和功能应用。该奖项还将支持本科暑期实习，这是针对专注于代表性不足的少数群体参与的高中生探索纳米技术的研讨会，以及国际学生交流。该项目旨在启用统一（而不是本地）PT的机制，并实现了可显着提高毛利（Mo）的塑性不良能力（MO）基于MOLYBDENUM（MO）np np np np np metals。极端应力（按照数十吉帕斯卡的顺序）需要热力学地从低能量体内的集中立方相驱动PT到高能面向居中的立方体，而不是激活脱位成核或传播机制。虽然在本地和原子量表上观察到了该PT，但尚不清楚它是否可以同质地发生，以显着修改大于大约一百纳米大约纳米的样品的机械行为。该项目将研究微结构特征的组合，包括1）小（无缺陷）韧带，2）结构的曲折和3）在MO和二级材料之间的接口，这将使高内部应力通过NP复合结构的全部均匀分布均匀分布，并促进均匀的变形和更好的耐牙。分子动力学模拟和具有有限元素分析的纳米力学测试实验将集成，以研究机械响应和验证后微观结构的潜在基于PT的均匀塑性变形。该奖项反映了NSF的法定任务，并认为使用该基金会的智力功能和广泛的影响来评估NSF的法定任务。