Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MM: Fachverband Metall- und Materialphysik
MM 39: Hydrogen in Materials II
MM 39.9: Vortrag
Freitag, 13. März 2026, 12:30–12:45, SCH/A215
Hydrogen induced strain instability in Aluminum — •Ali Tehranchi1,2, Bharathi Ganesh Ganesan Sekar1, and Tilmann Hickel1,2 — 1Bundesanstalt für Materialforschung und -prüfung (BAM), D-12489, Berlin, Germany — 2Max Planck Institute for Sustainable Materials, D-40237 Düsseldorf, Germany
Hydrogen embrittlement is a persistent form of metal degradation that arises from the complex interactions between hydrogen atoms and defects within metallic lattices. Environmental nanoindentation has become a standard experimental technique for probing these interactions, particularly the mechanisms underlying hydrogen-assisted deformation. In this work, we employ comprehensive large-scale molecular statics simulations in aluminum, complemented by ab initio calculations, to investigate the influence of hydrogen on homogeneous dislocation nucleation --the primary mechanism responsible for pop-in events observed under low-radius indenters. Our defect phase diagram analysis shows that, at hydrogen chemical potentials relevant to nanoindentation experiments, vacancy formation is significantly enhanced, leading to a substantial increase in the concentration of vacancy--hydrogen complexes. These complexes produce large local misfit strains, which in turn reduce the critical shear stress required for material instability and the onset of homogeneous dislocation nucleation.
Keywords: nanoindentation; homogeneous dislocation nucleation; hydrogen-defect interactions; defect phase diagram