Ti6Al4V alloys are widely used as a structural material. Open-cell porous Ti6Al4V alloys with different porosities are manufactured through powder bed fusion process. Cylindrical specimens consisting of ordered truncated octahedron unit-cells are designed using a 3D-CAD software. After the building, porous Ti6Al4V alloy specimens are annealed at different temperatures of 1173 and 1323 K for 1 h in vacuum. Vickers hardness of the annealed specimens is lower than those of as-built specimens. This is due to the increased volume fraction of beta phase which is measured by SEM observation and X-ray diffraction analysis. On the other hand, initial peak stress and energy absorption increase after the annealing because of the enhanced ductility of cell edges. Most specimens show the macroscopic shear band formation during compression tests, which causes the reduction of energy absorption. The ordered cell structure which is one of the reasons of the shear band formation is not suitable for energy absorbing applications.

A perovskite photo-sensor is promising for a lightweight, thin, flexible, easy-to-coat fabrication process, and a higher incident photon-to-current conversion efficiency. We have investigated perovskite photo-sensors with a solution-processed compact TiO2 under a low-temperature process and an ultra-thin polyethylenimine ethoxylated (PEIE) as an electron injection layer. The TiO2 film is grown from an aqueous solution of titanium tetrachloride (TiCl4) at 70 °C by a chemical bath deposition method. For an alternative process, the ultra-thin PEIE is spin coated on the TiO2 film. Then, the perovskite layer is deposited on the substrate by the one- or two-step methods in the glovebox. Next, a hole transport layer of 2,2,7,7-tetrakis(N,N-di-p-methoxyphenylamine)-9, 9-spiro-bifluorene (Spiro-OMeTAD) solution is spin coated. The fabricated device structure is a photodiode structure of FTO/TiO2/(without or with) PEIE/(one- or two-step) perovskite layer/Spiro-OMeTAD/Au. For the sensing characteristics, a ratio of photo-to-dark-current density was 2.88 × 104 for the device with PEIE layer. In addition, a power-law relationship is discussed.

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Relationship between the macroscopic and local strains of porous metals is examined by microstructural observation. Open-cell porous titanium with 60% porosity was compressed up to 30% macroscopic strain at room temperature. Open-cell porous nickel with 95% porosity was compressed up to 40% macroscopic strain at room temperature. Local strains in cell walls of both porous titanium and nickel were evaluated by electron backscatter diffraction (EBSD). Absolute value of the local strain increased with increasing the macroscopic strain and it is smaller than that of macroscopic strain. In addition, the value of the local strain at the cell junctions was larger than that of the center of cell struts.