University of Sydney researchers have directly observed hydrogen dissolved in the spaces between metal atoms, rather than only at defects [phys.org][scimex.org][nature.com]. The research, led by Professor Julie Cairney, was published in Nature. Hydrogen entering pipelines and storage equipment can cause cracking, a process known as hydrogen embrittlement [scimex.org]. The team used deuterium, a heavier hydrogen isotope, to trace hydrogen in metal alloys, combining atom-probe measurements with microscopy and calculations [scimex.org][nature.com]. First author Chao Huang said the next step is to test how hydrogen affects metal deformation and performance under stress, including in ultra-high-strength steels [scimex.org]. Highlights: • Detection method: The team used cryogenic atom-probe tomography to map deuterium in three dimensions. Isotope substitution helped distinguish the experimental signal from background hydrogen [scimex.org][nature.com]. • Alloy behaviour: In face-centred cubic multi-principal-element alloys, deuterium concentrated in phases with greater hydrogen affinity, and its levels varied with local chemistry and crystal structure [nature.com]. • Measurement challenge: Low hydrogen solubility, rapid diffusion and trapping at defects can make it difficult to distinguish dissolved hydrogen from other forms in atom-probe maps [nature.com]. "By identifying not only where hydrogen accumulates, but also why it prefers particular atomic environments, we can gain a deeper understanding of its fundamental behaviours in metals" — Professor Julie Cairney, research team leader at the University of Sydney Sources: • First direct observations reveal hydrogen dissolved in tiny gaps between metal atoms - phys.org • Observing hydrogen between metal atoms - scimex.org • Towards observing interstitial hydrogen in solution in metal lattices - nature.com --- 📰 Story aggregated by Kagi News