Atomic-Scale Imaging of Hydrogen in Metals Using Atom Probe Tomography

Student’s Name: José Montelongo Home Institution: Elmhurst University NNCI Institution: SHyNE @ Northwestern University REU Principal Investigator: Prof. David N. Seidman, Department of Material Science and Engineering REU Mentor: Dr. Amir R. Farkoosh, Department of Material Science and Engineering Dr. Dieter Isheim, Department of Material Science and Engineering Abstract: The United States sustains an annual direct cost of $276 billion due to corrosion, with hydrogen embrittlement (HE) standing out as a significant and costly form of material degradation, posing a risk to critical infrastructure including bridges, buildings, or pipelines. Additionally, hydrogen as a clean energy carrier requires materials that are resistant to HE. Hydrogen embrittlement is a phenomenon in which mobile hydrogen atoms permeates a material, causing significant deterioration of its mechanical properties, potentially leading to catastrophic structural failure. Understanding and mitigating this phenomenon is crucial for the durability and service life of structural components. One challenge in understanding the HE mechanisms is the difficulty in visualizing the distribution of hydrogen within the microstructure of a material. This study employs atom probe tomography (APT) to characterize on an atomic-scale the distribution of hydrogen in 3D printed (additively manufactured) stainless steel. APT provides an atomically resolved 3D image by analyzing individual atoms’ chemical identity and original position in a needle-shaped specimen of the material. Specialized computer programs are used to visualize the positions of the atoms within the sample. This information permits correlating the distribution of hydrogen atoms with microstructural features. The objective is to identify specific microstructural locations in the stainless steel to determine how H interacts with and embrittles a material at the atomic scale. Understanding these micro-nano mechanisms enables the implementation of effective manufacturing and processing strategies that enhance the performance and durability of materials in demanding environments, ultimately leading to more robust and cost-effective solutions.