Speaker
Description
Functional materials possess complex strain gradients that critically influence the performance characteristics of the technological components they constitute. These gradients may originate (i) from intentionally applied processing conditions, (ii) from self-organized phenomena, and/or (iii) from inhomogeneous thermal or mechanical loads experienced during service. To optimize component performance, it is essential to quantitatively assess strain gradients at the nanoscale and their evolution during operation. In this contribution, I will present experimental findings obtained by my group at the ID13 and ID03 beamlines of ESRF and the P07B beamline at PETRA III.
Cross-sectional synchrotron X-ray nanodiffraction (CSnanoXRD) [1], utilizing monochromatic X-ray beams with diameters down to ~25 nm, provides spatially resolved insights into the evolution of phases, crystallographic texture, grain morphology, and strain/stress distributions in nanocrystalline materials. I will discuss the methodological and instrumental aspects of the approach and highlight recent studies performed at the ID13 beamline. Examples will include thin films, nanomaterials and battery systems, with particular emphasis on in situ experiments and the analysis of complex depth gradients in microstructure–strain–property relationships [2,3].
Subsequently, strain characterization by dark-field X-ray microscopy (DFXM) at the ID03 beamline will be addressed. DFXM was employed to study Cu metallizations, revealing the origins of microscopic void and crack formation at high-angle grain boundaries (HAGBs). This behaviour is attributed to vacancy condensation in front of HAGBs, following dislocation motion across cyclically deformed grains. The observed HAGB decohesion correlates with local hardening near grain boundaries, as evidenced by X-ray diffraction peak broadening and elastic strain accumulation [4,5]. In addition, DFXM investigations of solid-state batteries—specifically dendrite growth in LLZO crystals—will be discussed [6].
Finally, recent high-energy X-ray diffraction studies of hydrogen–metal interactions, performed at the P07B beamline, will be presented. In situ experiments using custom electrochemical cells enabled us to elucidate the role of lattice swelling in the evolution of elastic strains, plastic deformation and hydride formation [7,8].
[1] Keckes et al., Acta Mat. 144 (2018) 862, https://doi.org/10.1016/j.actamat.2017.11.049
[2] Meindlhumer et al., Communications Materials 6 (2025) 35, https://doi.org/10.1038/s43246-025-00752-z
[3] Flatcher et al., Small 20 (2024) 2307515, https://doi.org/10.1002/smll.202307515
[4] Hlushko et al., Acta Mat. 253 (2023) 118961, https://doi.org/10.1016/j.actamat.2023.118961
[5] Ziegelwanger et al., npj Materials Degradation 9 (2025) 79, https://doi.org/10.1038/s41529-025-00629-z
[6] Yildirim et al., Nature Communications 15 (2024) 8207, https://doi.org/10.1038/s41467-024-52412-4
[7] Weiser et al., Acta Mat. 277 (2024) 120217, https://doi.org/10.1016/j.actamat.2024.120217
[8] Pogrielz et al., Corrosion Science 257 (2025) 113282, https://doi.org/10.1016/j.corsci.2025.113282