Small‐angle X‐ray scattering (SAXS) has become a standard tool for the investigation of nano‐structured materials with applications in many fields of science. Scanning tomography adds three‐dimensional information to the method. We investigate the validity of the tomographic model in SAXS tomography. We identify the requirement of local rotational invariance of the SAXS cross section and discuss the role of coherence in the framework of SAXS tomography. A tomography experiment performed on nanoporous glass is described as a practical example of the method. SAXS tomography reveals the density and nanostructure on a virtual section through a piece of nanoporous sodium borosilicate glass.

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Comparison of the structure of ancient Damascene steel blades at nanoscale with more recent ones -all made using crucible (wootz) technology and exhibiting ultra-high carbon content -showed for the first time a common feature. Despite different microstructures, colonies of wire-and tube-like particles with diameters of 40-50 nm have been observed with the aid of high-resolution transmission electron microscopy. Crystalline Fe 3 C is the main phase forming those particles covered in numerous cases by a tube-like layer. These tubes were also found in an empty or partly -covered filled variant. To assess the strengthening capacity of cementite various models were compared. Dispersion strengthening seems the most efficient. Cutting edge qualities may be related to surface corrugations due to nanoparticles. Dedicated to Prof. Wolfgang Neumann on the occasion of his 65th birthday

In situ application of an electric field to a SrTiO 3 single crystal plate during nanoindentation led to a reversible change of the mechanical properties at room temperature. When a field of 8 kV/cm was applied, Meyer hardness and Young's modulus decreased by 0.6 GPa and 11 GPa, respectively. An explanation for this behaviour is given by the diffusion of oxygen vacancies resulting in a distortion of the perovskite-type of structure in the near-surface layer tested by nanoindentation. Simulations using density functional theory support the dependence of elasticity on the presence of vacancies. Thus, we can show the remarkable influence of electric fields on oxide materials which should be considered and used in designing future applications.

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