Collaborative Research: Identifying Hydrogen-Density Based Laws for Plasticity in Polycrystalline Materials

氢引起的结构材料降解是航空航天、海洋、能源和基础设施领域意外部件故障的原因。同样，对氢引起的脆性的担忧是阻碍氢基燃料经济广泛采用的主要因素。目前防止这些故障的努力由于准确预测氢相关损伤及其对氢浓度的依赖而变得复杂。这项研究将使用实验和建模相结合的方法来解决这些问题，从而对氢如何影响材料行为产生新的基本理解。这项研究也将有利于国家福利在清洁能源的努力，使氢诱导损伤的预测条件下，氢辅助断裂的关注。此外，除了培养多名研究生外，该项目还将通过专门的活动、讲座和实验室演示，积极参与初高中学生的教育推广。该研究将确定氢是如何影响塑性损伤积累的，并利用已开发的见解来创建氢敏感的晶体塑性框架。首先，将采用常规（力学测试）和先进（高能x射线衍射）技术来阐明氢浓度对纯单晶和多晶Ni在单调和循环加载条件下变形行为的影响。其次，该数据集将用于推导一致的晶体滑移和硬化的氢敏感定律，其中包括氢对背应力发展和动态恢复的影响，从而可以用于广泛的氢浓度和加载条件。第三，将这些变形规律整合到晶体塑性框架中，并通过电子背散射衍射技术使用实验力学测试数据和微结构尺度弹性应变的空间分布进行验证，以证明模型的有效性。该研究将产生广泛的影响，因为氢信息晶体塑性框架将对支持氢基燃料经济性至关重要。此外，这项工作的所有实验数据将提供给研究界。初中和高中学生将通过互动虚拟实验室、案例研究和动手实验室调查来了解氢脆的关键问题，这些研究说明了氢对变形行为和潜在部件失效的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Hydrogen-induced degradation of structural materials is responsible for unexpected component failures across the aerospace, marine, energy, and infrastructure sectors. Similarly, concerns over hydrogen-induced embrittlement are a primary factor hindering the broader adoption of a hydrogen-based fuel economy. Current efforts to prevent these failures are complicated by challenges with accurately predicting hydrogen-related damage and its dependence on hydrogen concentration. This study will use a combined experimental and modeling approach to address these questions, resulting in new fundamental understanding of how hydrogen affects material behavior. This research will also benefit the national welfare in clean energy efforts by enabling the prediction of hydrogen-induced damage under conditions where hydrogen-assisted fracture is of concern. Moreover, in addition to training multiple graduate students, this project will actively engage in educational outreach with middle and high school students through dedicated events, lectures, and laboratory demonstrations.The researched study will establish how hydrogen affects plastic damage accumulation and leverage developed insights to create a hydrogen-sensitive crystal plasticity framework. First, conventional (mechanical testing) and advanced (high-energy X-ray diffraction) techniques will be employed to elucidate the effect of hydrogen concentration on the deformation behavior of pure single crystal and polycrystal Ni under monotonic and cyclic loading conditions. Second, this dataset will be leveraged to derive consistent hydrogen-sensitive laws for crystallographic slip and hardening that incorporate hydrogen effects on backstress development and dynamic recovery, enabling use for a wide range of hydrogen concentrations and loading conditions. Third, these deformation laws will then be integrated into a crystal plasticity framework, which will undergo validation using both experimental mechanical testing data and spatial distributions of microstructure-scale elastic strains via electron backscatter diffraction techniques to demonstrate model efficacy. The researched study will have broad impact as the hydrogen-informed crystal plasticity framework will be critical to supporting a hydrogen-based fuel economy. Additionally, all experimental data from this effort will be made available to the research community. Middle and high school students will get exposure and insight into critical issues for hydrogen embrittlement based on interactive Virtual Labs, case studies, and hands-on laboratory investigations that illustrate hydrogen’s effect on deformation behavior and potential component failure.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.