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Insights into the micro- and nano-architecture of materials is crucial for understanding and predicting their macroscopic behaviour. In particular, for emerging applications such as meta-materials, the micrometer scale becomes highly relevant. The micro-architecture of such materials can be tailored to exhibit specific mechanical, optical or electromagnetic behaviours. Consequently, quality control at micrometer scale must be guaranteed over extended areas. Mesoscale investigations over millimetre sized areas can be performed by scanning small angle X-ray scattering methods (SAXS). However, due to their long measurement times, real time or operando investigations are hindered. Here we present a method based on X-ray diffractive optics that enables the acquisition of SAXS signals in a single shot (few milliseconds) over extended areas. This method is applicable to a wide range of X-ray sources with varying levels of spatial coherence and monochromaticity, as demonstrated from the experimental results. This enables a scalable solution of spatially resolved SAXS. Mesoscale investigations of material microarchitecture using small angle X-ray scattering (SAXS) methods have been limited by long measurement times. Here, the authors present an X-ray diffractive optics method which enables single shot acquisition of SAXS signals over large areas.

Laboratory diffraction contrast tomography (LabDCT) enables the user to reconstruct three-dimensional (3D) grain maps of polycrystalline materials. For each grain, the size, orientation, and 3D morphology including the number of faces can be derived. Since the technique is non-destructive, LabDCT opens up new possibilities for studies of microstructural evolution at the level of individual grains. The LabDCT setup is integrated on a commercial X-ray microscope, enabling correlation of the resulting grain map with complimentary information on, e.g., cracks, porosities, and inclusions. Here, the LabDCT principle is introduced, and recent materials science applications are presented. The first example on liquid metal embrittlement highlights the correlation of grain boundary properties and complimentary absorption information on grain boundary wetting. It is shown that the grain boundary energy determines whether wetting occurs or not. The second example is on grain growth. The grain statistics in this study, more than 1200 grains at two different time steps, were large enough to capture rare events such as abnormal grain growth and the annihilation of a grain with only three faces.

Pinching is a process most commonly associated with the break-up of liquid streams in air. Time-resolved three-dimensional X-ray imaging of a eutectic Al–Cu alloy reveals that interfacial-energy-driven bulk diffusion can drive similar processes in liquid–solid systems As rodlike domains pinch off owing to Rayleigh instabilities, a finite-time singularity occurs as the interfacial curvature at the point of pinch-off becomes infinite. The dynamics controlling the interface become independent of initial conditions and, in some cases, the interface attains a universal shape 1 . Such behaviour occurs in the pinching of liquid jets and bridges 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 and when pinching occurs by surface diffusion 10 , 11 , 12 . Here we examine an unexplored class of topological singularities where interface motion is controlled by the diffusion of mass through a bulk phase. We show theoretically that the dynamics are determined by a universal solution to the interface shape (which depends only on whether the high-diffusivity phase is the rod or the matrix) and materials parameters. We find good agreement between theory and experimental observations of pinching liquid rods in an Al–Cu alloy. The universal solution applies to any physical system in which interfacial motion is controlled by bulk diffusion, from the break-up of rodlike reinforcing phases in eutectic composites 13 , 14 , 15 , 16 to topological singularities that occur during coarsening of interconnected bicontinuous structures 17 , 18 , 19 , 20 , thus enabling the rate of topological change to be determined in a broad variety of multiphase systems.

Sustainable buildings have often been niche products, but in recent years a new approach has emerged in Denmark aimed at mainstreaming and normalizing this mode of construction and seeking to attract ordinary Danes through market conditions. The aim is to present an alternative conceptualization of sustainable buildings to the ecocommunities' vision and to involve traditional building firms in their design and development. From a theoretical perspective, the mainstreaming of sustainable buildings can be seen either as an example of ecological modernization or technological transition. The new conceptualization has implied a narrower approach to sustainability and a lack of social sustainability measures. While earlier paradigms of sustainable buildings emphasized themes such as community building, self-provisioning, local empowerment, and shared facilities, such objectives are largely absent in the new types of sustainable buildings. We question to what extent it is possible to design sustainable settlements without social sustainability. By viewing sustainable buildings as technological configurations, we argue that the multiactor approach, fragmentation of roles, and absent initiatives for social sustainability influence the buildings' environmental performance and should be important for the next generation of these structures.

Laboratory diffraction contrast tomography (LabDCT) is a laboratory-scale x-ray microtomography technique that can be used to non-destructively map grains and grain boundaries in 3D. The fidelity of grain mapping significantly depends on the quality of grain reflections obtained from the illuminated volume of the specimen. In this article, we report the application of a novel forward modeling approach to improve the reliability of grain mapping. Through this approach, a comparison between the obtained grain reflections and simulated grain reflections can be used to perform a self-fitting operation. This can be used to optimize instrumental parameters and iteratively improve the quality of reconstruction. To demonstrate the effectiveness of the forward modeling approach, LabDCT was used to map the grains in a polycrystalline specimen of the magnesium alloy AZ91E and iteratively improve reconstruction quality significantly.

The ability to watch the three-dimensional (3D) evolution of structural materials is a breakthrough in non-destructive characterization. In particular, X-ray tomographic imaging techniques have found success in revealing the underlying mechanisms of microstructural transformations in partially and fully solidified metals. Here we review the most important developments in four-dimensional X-ray microscopy, focusing on absorption- and diffraction-based techniques in the laboratory and the synchrotron. In light of recent progress in this area, we identify critical issues that point to directions for future research in imaging the evolution of heterogeneous microstructures at extreme space and time scales. IMPACT STATEMENT Four-dimensional X-ray tomography has opened a new paradigm in physical metallurgy, allowing us to characterize the various epochs of microstructural evolution in 3D and as a function of time.

Laboratory diffraction contrast tomography (LabDCT) enables a user to reconstruct 3D grain maps of polycrystalline materials non-destructively. For each grain, the morphology and crystallographic orientation, as well as derived properties such as grain boundary properties can be determined. Through two application examples this paper demonstrates the capabilities and potential of the current LabDCT implementation. Firstly, for well-annealed grain structures the reproducibility of LabDCT for more than 95% of the grains was found to be 5 μm on grain center-of-mass positions and 0.02° on orientations, while 90% of the grain boundary locations are determined with an accuracy better than 4 μm. The second example highlights the available statistics on thousands of grains, as well as the complementarity between LabDCT and absorption contrast tomography, readily available due to the integration of LabDCT on a commercial X-ray microscope