Nanoindentation, High-Temperature Behavior, and Crystallographic/Spectroscopic Characterization of the High-Refractive-Index Materials TiTa2O7 and TiNb2O7.

Colorless single crystals, as well as polycrystalline samples of TiTa2O7 and TiNb2O7, were grown directly from the melt and prepared by solid-state reactions, respectively, at various temperatures between 1598 K and 1983 K. The chemical composition of the crystals was confirmed by wavelength-dispersive X-ray spectroscopy, and the crystal structures were determined using single-crystal X-ray diffraction. Structural investigations of the isostructural compounds resulted in the following basic crystallographic data: monoclinic symmetry, space group I2/m (No.

Microstructure-stiffness relationships of ten European and tropical hardwood species.

Hardwood species exhibit a huge anatomical variability. This makes them perfect study objects for exploring relations between structural features at different length scales and corresponding stiffness properties of wood. We carry out microscopic analysis, nanoindentation tests, as well as macroscale ultrasonic and quasi-static tension tests and build a complete set of microstructural and corresponding micromechanical data of ten different (European and tropical) hardwood species.