Speaker
Description
Across a wide-range of applications in materials science, there is growing interest in being able to accurately detect, locate and quantify the presence of hydrogen in the microstructures of materials. These include modern high-strength steels, Ni-alloys and Ti-alloys for aerospace and other engineering applications, broadly aiming to understand how to make components more resistant to the embrittling effects of hydrogen. In a similar vein, a wide array of metallic surfaces exposed to extreme environmental conditions of irradiation and high temperatures in nuclear applications (both fission and fusion processes) can see hydrogen ingress, and understanding the extent and rate of this is crucial to predicting component lifespans.
While APT instrumentation can routinely detect hydrogen in various forms, accurately quantifying this is uniquely prone to difficulties decomposing any true signals from levels of contaminant or background hydrogen inside the atom probe vacuum chamber. We have developed a number of approaches to help tackle this problem, such as using deuterium (D+) ions as a proxy for hydrogen in a variety of different experimental charging protocols. This has been done in parallel with concerted efforts to both determine the likely level of expected background hydrogen peaks and to minimize these by systematically varying the instrument analysis conditions. A number of such studies will be presented along with suggested strategies for future experiments in this area.
[1] M. S. Meier, M. E. Jones, P. J. Felfer, M. P. Moody, and D. Haley, “Extending Estimating Hydrogen Content in Atom Probe Tomography Experiments Where H2 Molecule Formation Occurs,” Microsc. Microanal., vol. 28, no. 4, pp. 1231–1244, Aug. 2022, doi: 10.1017/S1431927621012332.
[2] M. S. Meier, P. A. J. Bagot, M. P. Moody, and D. Haley, “Large-Scale Atom Probe Tomography Data Mining: Methods and Application to Inform Hydrogen Behavior,” Microsc. Microanal., vol. 29, no. 3, pp. 879–889, Jun. 2023, doi: 10.1093/micmic/ozad027.
