CAREER:Quantifying Radiation Damage in Metals with Wigner Energy Spectral Fingerprints

金属“损害”的概念仍然很难量化。金属是我们最重要的结构材料之一，为从建筑物到桥梁再到核反应堆的一切提供了支柱。如果我们有一种通用的方法来测量损伤，我们就能够更好地预测金属何时失效，测量它们在服役期间的退化，并设计出既耐用又更经济的新金属。建议使用储存能量指纹作为一种方法来量化任何破坏过程对金属的损害。我们专注于辐射损伤，认为这是制造金属中所有类型缺陷的理想方法。将使用双管齐下的实验和模拟方法来量化和理解这些存储的能量指纹，将它们与损伤造成的缺陷直接联系起来。这项工作的直接应用范围从调和离子和中子辐射之间的差异，到预测辐射损伤引起的材料性质变化，到核实铀浓缩离心机的历史使用情况。这种加深的理解也将是降低其学习门槛的关键，为实践教学和将更多代表不足的少数族裔(URM)学生纳入目前STEM中最不多样化的领域之一创造了全新的机会。技术我们理解材料如何对损伤做出反应的能力受到限制，因为我们缺乏对损伤过程中产生的微结构缺陷的准确群体的了解。这一问题在辐射材料科学领域最为普遍，在该领域，缺乏可测量的辐射损害单位继续混淆了在电离辐射下材料性能退化的量化机制。如果已知受损材料中每个缺陷的全部总体，则可以利用现有的结构-性能关系来预测其材料性能。我们建议使用存储能量指纹来可视化由任何类型的损伤，特别是辐射引起的全部过多的缺陷。我们从一个长期被忽视的想法中获得灵感，该想法指出，辐射损伤应该像非晶化或冷功一样储存能量。这一概念被扩展到描述金属中所有形式的微结构损伤，以一种可测量的方式揭示了相关的缺陷。使用时间加速的并行复制动力学模拟和超快纳米量度测量，我们将直接将模拟和测量的中尺度存储能量释放与原子理解联系起来。这将使对受损金属的存储能量指纹的后验测量成为可能，揭示出相关的原子配置和缺陷数量。因此，我们试图提供由损伤引起的缺陷的全貌，展示一种测量它们的方法，使用原子模拟来解释它们的演化，并创建统一的理论来预测金属中由损伤引起的缺陷结构和所产生的材料性质。

Non-Technical The concept of "damage" to a metal remains difficult to quantify. Metals are among our most important structural materials, providing the backbone to everything from buildings, to bridges, to nuclear reactors. If we had a universal way to measure damage, we would be able to better predict when metals would fail, measure their degradation during service, and design new metals to be both longer-lasting and more economical. The use of stored energy fingerprints is proposed as a way to quantify damage to metals from any damaging process. We focus on radiation damage as an ideal way to make all the types of defects found in metals. A two-pronged experimental and simulation approach will be used to quantify and understand these stored energy fingerprints, relating them directly to the defects created by damage. Immediate applications of this work range from reconciling the differences between ion and neutron irradiation, to predicting material property changes due to radiation damage, to verifying the historical usage of uranium enrichment centrifuges. This enhanced understanding will also be the key to lowering the barriers to its study, creating completely new opportunities for both hands-on instruction and inclusion of more underrepresented minority (URM) students into what is currently one of the least diverse fields in STEM.Technical Our ability to understand how materials respond to damage is limited by our lack of understanding about the precise populations of microstructural defects created during damage processes. Nowhere is this issue more prevalent than in the field of radiation materials science, where the lack of a measurable unit of radiation damage continues to obfuscate the quantitative mechanisms responsible for the degradation of material properties under ionizing irradiation. Were the full populations of every defect in a damaged material to be known, then its material properties could be predicted with existing structure-property relations. We propose to use stored energy fingerprints to visualize the full plethora of defects resulting from damage of any kind, particularly irradiation. We draw inspiration from a long-neglected idea stating that radiation damage should store energy like amorphization or cold work. This idea is extended to describe all forms of microstructural damage in metals, in a measurable way which reveals the defects responsible. Using time-accelerated parallel replica dynamics simulations and ultra-fast nanocalorimetric measurements, we will directly link simulated and measured stored energy releases at the mesoscale, with atomistic understanding. This will enable a posteriori measurements of stored energy fingerprints of damaged metals, revealing the atomic configurations and quantities of defects responsible. Thus we seek to provide the full picture of defects resulting from damage, demonstrate a method to measure them, explain their evolution using atomistic simulations, and create unifying theories to predict the defect structures and resultant material properties resulting from damage in metals.