The distribution of lithium in nickel‐cobalt‐aluminium (NCA) cathodes and graphite anodes of cylindrical (18650) high‐energy lithium‐ion batteries was studied using a combination of neutron‐ and synchrotron‐based diffraction computed tomography (DCT). The in‐plane lithium concentration in the positive and negative electrodes was assessed in situ at various nominal states of charge and health. DCT is one of the few techniques that enable non‐destructive examination of electrochemical storage systems such as batteries. Several DCT configurations were explored, with probe‐beam sizes ranging from millimetres to a few micrometres, demonstrating the method's capability across different length scales. The use of thermal neutrons as a probe in DCT was demonstrated for structural studies of lithium‐ion batteries, where the results were compared to similar studies using high‐energy photons. In addition, a region‐of‐interest approach for X‐ray DCT was successfully demonstrated for the non‐destructive characterisation of electrochemical storage systems.

Single-crystal elastic constants (SECs) of an oxygen-doped TiNbVZr high-entropy alloy are determined by in situ three-dimensional X-ray Diffraction (3DXRD) as C11 = 150.4 GPa, C12 = 98.6 GPa, C44 = 35.1 GPa. However, a single set of SECs cannot accurately reproduce grain-specific Young's moduli (R2 = 0.76). This scatter may be associated with intrinsic chemical heterogeneity and short-range order.

The precise characterization of near-surface residual stress is critical for in-service fatigue performance in high-strength components, yet conventional techniques often lack the depth-resolution to capture steep micrometer-scale gradients and their crystallographic (hkl-dependent) variations. In this study, depth-resolved residual strain and stress tensors in machined and shot peened Inconel 718 were quantified using high-energy synchrotron X-ray diffraction (HEXRD) combined with full Debye–Scherrer ring analysis. The as-machined surface exhibits high tensile in-plane stress, accompanied by pronounced hkl-dependent strain partitioning, particularly along the cutting direction. Shot peening transforms this state into a compressive in-plane condition and redistributes the anisotropic residual strain and stress field. While the hkl-dependent variation is reduced along the cutting direction, it remains present in other orientations, indicating a partial suppression of crystallographic anisotropy. Although the hkl-averaged out-of-plane stress remains close to zero at the free-surface, as expected for the macroscopic stress component, significant hkl -dependent stress variations persist, suggesting a fine domain size and intergranular stress heterogeneity. Strain pole figure representation further shows that machining produces a strongly direction-dependent strain distribution, whereas shot peening leads to a more uniform and nearly axisymmetric strain field with weak directional variations. The full-ring HEXRD approach enables quantitative characterization of multiaxial residual stress tensors and their crystallographic dependence and enables excellent grain statistics at high depth resolution. The results provide a detailed description of the depth-dependent redistribution of residual strain and stress following sequential surface treatments which forms the basis of the understanding of fatigue performance of safety-critical alloys.

An Nb-layer-free NbTi/Cu multilayer composite is proposed for superconducting shielding applications. Coldrolled Nb-53 wt% Ti and oxygen-free high-thermal-conductivity (OFHC) Cu sheets were assembled in a copper cassette and processed into a structurally homogeneous composite with a final thickness of 0.5 mm by hot rolling at 700 degrees C, followed by cold rolling at room temperature. Microstructural analyses reveal excellent chemical and morphological stability of the NbTi/Cu interfaces. No Cu-Ti intermetallic compound formation is detected after intermediate ageing at 375 degrees C for 12 h at 1 mm thickness, nor after prolonged heat treatment in the final state. This stability is preserved despite the intentional omission of a Nb diffusion barrier layer. Extended ageing for 672 h induces the formation of non-equilibrium Widmansta & uml;tten alpha-Ti precipitates within the NbTi matrix, accompanied by a high dislocation density in both the precipitates and the parent beta-NbTi phase. These features provide effective flux-pinning sites without compromising interfacial integrity. The Nb-free multilayer design simplifies processing, reduces material cost, and enhances the stabilising role of copper, offering a robust microstructural platform for superconducting shield applications.

Multilayered metallic composites have attracted widespread attention in both scientific and engineering communities owing to their exceptional mechanical properties. Clarifying the anisotropic mechanical behavior and the underlying deformation mechanisms is the premise for the successful application of those materials. In this study, the anisotropic plasticity and damage of multilayered Ti/Nb composites processed by accumulative roll bonding were investigated using synchrotron-based X-ray diffraction during tensile deformation. When comparing the uniaxial tension along rolling direction (RD) and transverse direction (TD), the laminates do not show obvious plastic anisotropy, but have significant anisotropic neck-to-fracture behavior. Residual stress, along with texture, contributes to the absence of anisotropy in yield strength. Under different loading directions, similar dislocation densities in each constituent metal, resulting from the similar grain morphologies, are responsible for the consistent ultimate tensile strengths. The collective hardening effect of the constituent metals results in the insignificant difference of work hardening in the bulk laminates. After necking, the faster degradation of mechanical property, namely the higher decreasing rate of flow stress, of the bulk composites loaded along the TD is attributed to the larger stress triaxiality of the Nb {211} grains (i.e. <211> // loading direction) that accelerates micro-void growth in the Nb layers as well as the more universal decohesion of hetero-interfaces between the different metals. These findings provide a comprehensive and in-depth understanding of the anisotropic plasticity and fracture behaviors, as well as the micromechanisms of Ti/Nb composites, which gives new insights to excavate the forming potential for multilayered metallic composites.

In this work, structural changes at high heating rates of Fe 74 Mo 4 P 10 C 7.5 B 2.5 Si 2 metallic glass were studied using high energy synchrotron radiation with microsecond time resolution. Amorphous ribbons before and after isothermal heat treatments at different temperatures were analyzed by laboratory X-ray diffraction (XRD) and differential scanning calorimetry (DSC). In addition, Flash DSC (FDSC) measurements were performed in the laboratory to investigate the crystallization behavior at high heating rates. This study investigates heating rates from 0.08 K/s to 10000 K/s, covering five orders of magnitude. Thermal cycling at high heating rates showed a broadening of the supercooled liquid region and a decreased activation energy of crystallization. Employing high-energy synchrotron radiation during FDSC measurements and comparing it to laboratory XRD isothermal heat-treated samples show different crystallization behavior due to the formation of metastable phases like gamma- Fe, which is retained at room temperature at high cooling rates.

The anisotropic microstructure and strengthening mechanisms of laser powder bed fused (L-PBF) Inconel 718 (IN718) superalloy were comprehensively investigated using experimental and theoretical analyses. Due to the complex thermal gradient and history, the cell structure evolved heterogeneously along the building direction (BD), exhibiting coarser dimensions with increasing distance from the baseplate. This unique microstructural feature played a dominant role in the anisotropic tensile properties (i.e. yield strength and strain hardening behavior) between the loading direction (LD) parallel and normal to BD. To deeply explore the correlation between the directional flow behavior and the various cellular configurations, in-situ high-energy X-ray diffraction (HEXRD) during tensile loading together with multiscale microstructural characterization was performed. It was revealed that the different yield strengths were primarily induced by the heterogeneous cell structures that experienced distinct thermomechanical histories, rather than by crystallographic texture. Furthermore, the more pronounced strain hardening capability observed in the horizontal specimen (loading normal to BD) was attributed to the strong dislocation-boundary interactions, inhibited microvoid formation and growth in the < 200 > //LD grains, and enhanced micro stress responses in the < 111 > //LD and < 200 > //LD grains. These findings offer new insights into the fundamental mechanisms governing the anisotropic mechanical behavior of L-PBF alloys.

The strength-ductility trade-off has hindered the widespread application of powder metallurgy (PM) titanium matrix composites (TMCs). In-situ planting nano-particles as ultra-fine networks into the TMCs powder and constructing the interfacial/intragranular hierarchical microstructure have emerged as a promising strategy to overcome the strength-ductility trade-off. In the present work, we precisely controlled the distribution of the network nano-particles by adjusting the sintering temperatures and successfully transformed the ultrafine network into the interfacial/intragranular structure. The well-designed (TiB + La2O3)/IMI834 TMCs demonstrated exceptional mechanical properties, achieving a tensile strength of 1158 MPa while maintaining an elongation exceeding 8.6 %-performance comparable to wrought TMCs without requiring thermo-mechanical processing. The dislocation evolution and the slip activation behavior were investigated by in-situ synchrotron Xray diffraction experiments and interrupted in-situ SEM-EBSD observations, which provided new insights into the strength-ductility synergy mechanism of the interfacial/intragranular nano-particles. These studies revealed that the hierarchical structure enhanced the dislocation storage capacity while simultaneously promoting slip activation. This dual effect facilitated multi-system sliding, which effectively optimized dislocation distribution and reduced stress concentration. This study visually elucidates the synergistic strength-ductility mechanism of the interfacial/intragranular hierarchical structure and establishes a straightforward and reliable approach for manufacturing high-performance PM TMCs.

In-situ high-energy X-ray diffraction experiments under uniaxial loading revealed the stress distribution among austenite, ferrite, and nanoscale B2-(Ni,Fe)Al intermetallic precipitates embedded in the ferrite phase of an Al-added lightweight steel. Stress analysis based on the lattice strains induced by uniaxial tensile loading, while assuming a uniaxial stress state within the grains and neglecting residual stresses, indicated earlier yielding of austenite and the development of higher stresses in ferrite. Remarkably, at an applied true stress of nearly 1.0 GPa, stresses up to about 5.8 GPa were determined within the B2 precipitates. The stress level within the B2 precipitates, which exhibited a bimodal size distribution, was strongly size-dependent, with the finer population experiencing higher stresses. Due to the low Schmid factor for {hkl}(100) slip as the preferred slip system in B2, plastic deformation of B2 in this hard orientation was enabled by (111) slip, aided by the penetration of 12 (111) dislocations gliding on {110} planes in the cube-on-cube-related ferrite. The high stresses in B2 upon loading along the (100) direction raised the stress level in the surrounding ferrite, which is a likely cause of {100} cleavage in embrittled body-centered cubic steels. This study enhances our understanding of the micro-mechanical behavior of precipitation-strengthened alloys and elucidates how matrix-precipitate interactions influence macroscopic mechanical properties.

Powder bed fusion laser beam (PBF-LB) is particularly effective for fabricating compositionally complex alloys such as high-entropy alloys (HEAs) or medium-entropy alloys (MEAs). Fabricating non-equiatomic metastable MEAs using PBF-LB can lead to the formation of unique microstructures that enhance the mechanical performance of these alloys. Nevertheless, plastic anisotropy in materials prepared by additive manufacturing routes including PBF-LB remains to be a technical challenge. This work presents the fabrication of a metastable nonequiatomic Co45Cr25(FeNi)30 MEA using PBF-LB. As-printed samples exhibited the formation of nano-scaled epsilon-martensite (HCP) phase along with the FCC phase. The HCP phase exhibited Shoji-Nishiyama orientation relationship with the FCC phase. High energy synchrotron X-ray diffraction (HEXRD) and electron backscatter diffraction (EBSD) in-situ tensile testing were employed to investigate the influence of the HCP phase on the alloy's deformation behavior. The presence of the HCP phase initiates stress-induced martensitic transformation well below the macroscopic yield strength. This transformation led to the non-linear stress and strain response for the FCC phase. Further straining resulted in significant load partitioning, with the HCP phase taking the majority of the load as it formed, significantly strain hardening the alloy and reducing the plastic anisotropy induced by texture in the as-printed material.

Passivity refers to spontaneous formation of a passive film on the surface of metals. High stability of the passive film on advanced alloys relies on the repassivation ability of the alloys in corrosive environments. Two Ni-base superalloys (Ni-22Cr-9Mo-5Fe-2Nb and Ni-18Cr-3Mo-20Fe-5Nb) are studied to elucidate the mechanism of repassivation through a combination of multimodal in-situ synchrotron X-ray measurements, electrochemical measurements, and first principles calculations. The synchrotron X-ray analyses enabled in-situ probing of the passive film and the hidden subsurface alloy layer. The results reveal chemical and structural evolutions of both the passive film and the underlying subsurface alloy layer under transpassive condition. The first principles calculations demonstrate a crucial role of the subsurface alloy layer in the repassivation of the alloys. Upon passivity breakdown at high electrochemical potentials, the passive film rich in Cr oxide becomes highly defective with vacancies, and metal dissolution leads to generation of vacancies (mainly Ni) in the subsurface alloy layer. This promotes repassivation process by enhanced outward Cr diffusion strengthening the metal bond (more Cr-Ni bonds) in the subsurface alloy layer and, together with the enrichment of high valence Mo- and Nboxides in the passive film, lead to repassivation when the high potential is removed, which is different from Ferich alloys.

Objective.Synchrotron-based spatially fractionated radiotherapy and ultra-high dose rate (UHDR) radiotherapy have been shown to better spare healthy tissue function in comparison to conventional radiotherapy, while controlling the tumour with the same efficacy. In recent years, an increasing amount of research has been carried out in these fields with promising results. However, further experiments remain essential, since the underlying mechanisms of healthy tissue preservation are not yet fully understood. The characterisation of synchrotron beamlines at the Deutsches Elektronen-Synchrotron in Hamburg represents an opportunity to increase the number of sites where pre-clinical studies could be conducted in the future. However, the beams available at this synchrotron are only a few millimetres in size and measuring absorbed dose with established detectors and dosimetry protocols represents a challenge.Approach.We show a procedure to accurately determine the beam dose rate under such conditions by first characterising a monochromatic beamline. After validation, and with the support of Monte Carlo simulations, the procedure is adapted to investigate a white-beam beamline, at which photon flux and mean energy can be varied with Cu absorbers.Main results.With the developed procedure, it is possible to measure absorbed dose at these beamlines with relative uncertainties below 10%. In particular, at the white-beam beamline, the dose rate varies between about 20 Gy s-1and about 1800 Gy s-1, thus offering the opportunity to carry out much-needed systematic studies. Moreover, pilot experiments with a mouse phantom demonstrate that it is possible to treat small animals with such small-sized beams by using dose-painting techniques, with an agreement between prescribed and delivered dose within ±15%.Significance. This work represents a first step towards the implementation of reproducible pre-clinical studies at the PETRA III synchrotron, further contributing to a transition of spatially-fractionated and UHDR radiotherapy techniques into clinical practice.

Recently, the promising multi-component magnetocaloric materials (Mc-MCMs) are found to have a tunable giant magnetocaloric effect (GMCE) near room-temperature and manifest fruitful functionalities like multicaloric effects, which are candidates for solid-state caloric applications. Introducing vacancy defects is found to be an efficient method to optimize its GMCE property. However, the responsible mechanism and especially the characteristics of the atomic vacancies are far from being elucidated. Here, we produce direct-solidified MnCoNiGeSi-based Mc-MCMs which exhibit the distinct shift in transition temperature (Tt) upon introducing Mn/Ni vacancies. It is found that Tt decreased significantly in the Mn vacancy materials and increased in the Ni vacancy materials. The first-order transition is maintained and the strength of the magnetic entropy change (Delta sm) was unchanged without degradation. For the Mn vacancy sample the decreased Mn-Mn atomic distance and strengthened covalent bonding can stabilize the high-temperature hexagonal phase, while for the Ni vacancy sample the decreased interatomic distances among different pairs (Mn-Ge, Mn-Mn and Mn-Ni) promote the stabilization of the low-temperature orthorhombic phase. Additionally, the introduced vacancy defects have directly been observed through HAADF-STEM. Positron annihilation results clarified the mono-vacancy nature for these vacancies, and indicate that the Ni positions around the Ni vacancies could partially be occupied by Mn atoms. Our study reveals that introducing atomic vacancy defects can effectively regulate the magnetocaloric properties and provide important fundamental insights into defect engineering of Mc-MCMs.

The deformation mechanisms of Zn- and Al-alloyed Mg were investigated using in-situ three-dimensional synchrotron X-ray diffraction (3DXRD). The activation of basal and prismatic slip was quantified in Mg-1Al (A1), Mg-1 Zn (Z1), and Mg-1Al-1 Zn (ZA11) alloys in order to assess the influence of solute alloying on slip system competition. The results reveal that the combined addition of Zn and Al facilitates prismatic slip activation by reducing its critical resolved shear stress (CRSS), and leads to the lowest RSSprism/RSSbasal ratio of 5.44, compared to 6.25 in A1 and 6.23 in Z1. This indicates a more balanced activation of basal and non-basal slip systems. Grain rotation analysis further suggests that ZA11 accommodates deformation more effectively through non-basal slip, reducing stress localization. These findings provide direct insights into how solute interactions influence slip system activity and offer guidelines for optimizing Mg alloys for improved ductility and mechanical performance.

Tomographic surface X-ray diffraction (TSXRD) is an adaptation of classic surface X-ray diffraction to allow for measurements of polycrystalline surfaces. Compared to most other surface-sensitive techniques, surface X-ray diffraction has advantages in operando studies, since it can provide crystallographic information about surface structures in high gas pressures (above atmospheric) as well as through liquids. The method has, however, so far been limited to ideal samples, such as single crystals, since the long beam footprint illuminates several grains, which, with conventional SXRD, prevents an assignment of the diffraction signal and thus the structural information, to a certain grain. Here, we present the first step in the development of TSXRD, in which the grain shapes and orientations on a polycrystalline surface can be mapped using grazing incidence X-ray diffraction. The resulting knowledge about the shape, position, and orientation of the grains at the surface will be the steppingstone for further SXRD analysis of polycrystalline surfaces, allowing us to identify which diffraction signals belong to which grain. This method is thus part of opening up SXRD as a method for operando studies of more industry-relevant samples. Our grain maps are compared to those obtained with electron back-scatter diffraction measurements of the same sample, confirming the validity of the method.

This study investigates the impact of silicon content in the graphite anode of cylinder-type Li-ion batteries using operando neutron powder diffraction techniques. A batch of four different Li-ion cells is analyzed, with a focus on the structural response of active cell components during electrochemical cycling. The results indicate that high silicon content in the graphite anode causes a delay in the initial lithiation of graphite, shifting it towards higher voltages independent of the cell's internal resistance. Differential voltage, incremental capacity analyses and quantitative energy-dispersive X-ray spectroscopy, corroborate these structural changes. Additionally, X-ray diffraction computed tomography using a mu m-sized synchrotron beam revealed local structural degradation and lithiation inhomogeneity in the high silicon content cells during cycling.

Protons are increasingly used as a surrogate for neutrons to study radiation damage of engineering alloys used in the core of a nuclear reactor, enabling high fluences in comparatively short times. However, the accelerated damage rate of protons is usually compensated by an increased irradiation temperature to assist diffusion. To better understand dose rate effects on microstructure evolution during radiation damage, recrystallized Low-Sn ZIRLO and Zircaloy-2 were proton-irradiated to 0.15 dpa at 320 degrees C using nominal dose rates of 1.3, 2.5, and 5.2 x 10-5 dpa/s. Depth profiling using microbeam synchrotron XRD was conducted across the 30 mu m deep irradiated regions for line profile analysis, enabling dislocation line density determination. We found no significant difference in dislocation density among the different dose rates for Zircaloy-2 while Low-Sn ZIRLO displayed dose rate sensitive microstructural evolution. However, Low-Sn ZIRLO exhibited a significantly lower overall dislocation density compared to Zircaloy-2 samples at all dose rates. (S)TEM analysis of the samples showed clear (a) loop alignment in Zircaloy-2, while this was less pronounced in Low-Sn ZIRLO. APT analysis conducted on Low-Sn ZIRLO specimens showed the early onset of irradiation induced nanoclusters of Nb, where the clusters were observed to be comparatively smaller in the sample exposed to high dose rate irradiation. Overall, the integration of different techniques has provided a more comprehensive understanding of the early-stage damage evolution under differing damage accumulation rates.

Bulk nanostructured metals introduced by severe plastic deformation contain an excess of lattice defects. A nanostructured copper (Cu) processed by a high-pressure torsion technique was examined during in situ heating to investigate microstructural relaxation and quantify the evolution of microstructural parameters using highenergy synchrotron microbeam X-ray diffraction. While general microstructural relaxations, such as recovery, recrystallization, and subsequent grain growth, were observed, the key microstructural parameters, including grain size, microstrain, dislocation density, and thermal expansion coefficient, and their changes at critical temperatures were uniquely described and quantified through diffraction data. Based on this analysis, the stored energies driving thermally activated microstructural changes were estimated for individual defect types - grain boundaries, dislocations, and vacancies - that are expected to significantly influence the relaxation behavior of nanostructured Cu. This study demonstrates the effectiveness of diffraction characterization techniques for gaining a comprehensive understanding of the thermal stability of bulk nanostructured materials.

The magnesium alloy AZ31, which has undergone high-pressure torsion processing, was subjected to in situ annealing microbeam synchrotron high-energy X-ray diffraction and compared to the as-received rolled sheet material that was investigated through in situ neutron diffraction. While the latter only exhibits thermal expansion and minor recovery, the nanostructured specimen displays a complex evolution, including recovery, strong recrystallization, phase transformations, and various regimes of grain growth. Nanometer-scale grain sizes, determined using Williamson–Hall analysis, exhibit seamless growth, aligning with the transition to larger grains, as assessed through the occupancy of single-grain reflections on the diffraction rings. The study uncovers strain anomalies resulting from thermal expansion, segregation of Al atoms, and the kinetics of vacancy creation and annihilation. Notably, a substantial number of excess vacancies were generated through high-pressure torsion and maintained for driving the recrystallization and forming highly activated volumes for diffusion and phase precipitation during heating. The unsystematic scatter observed in the Williamson–Hall plot indicates high dislocation densities following severe plastic deformation, which significantly decrease during recrystallization. Subsequently, dislocations reappear during grain growth, likely in response to torque gradients in larger grains. It is worth noting that the characteristics of unsystematic scatter differ for dislocations created at high and low temperatures, underscoring the strong temperature dependence of slip system activation. Graphical Abstract

This study investigates the microstructural characteristics and mechanical properties of a laser welded AZ80 magnesium alloy. The welding process led to the formation of coarse-grained fusion zone (FZ), where a secondary phase formed continuous network. Mg17Al12 precipitation and coarsening of grain boundaries occurred in the heat affected zone. The welded joint exhibited excellent mechanical properties with a yield strength of 202 MPa and a joint efficiency of 92%. The microstructure analysis via EPMA and EBSD in conjunction with synchrotron X-ray diffraction analysis reveals that precipitates and increased dislocation density in the fusion zone are primary strengthening mechanisms for the laser welded AZ80 Mg alloy.