By using the millimeter-wave or a kind of microwaves with short wave length, fabrication of ceramics with uniform morphology and examples of low temperature rapid sintering have been reported. Since the sintering progresses from the interior even with the rapid temperature increasing, it has been found that pores do not easily remain in the interior even if pressure sintering is performed afterwards, and the thermal conductivity of the heat radiation substrate is improved. We also reported diffusion promotion of cations which seems to contribute to the short-time sintering. We found zirconia ceramics having a composition which is easy to process using its plastic deformation during millimeter-wave heating and has creep resistance at elevated temperature with conventional heating. We have found improvement of oxide ion conductivity under irradiation with millimeter-waves in various added zirconia, ceria and LaGaO₃ based ceramics and improvement of power generation properties of solid oxide fuel cells using these materials as an electrolyte. Improvement of mass transfer including diffusion was more pronounced in ion species with large millimetre-wave absorption, but it could not be explained by this alone, and comprehensively explained by non-thermal effect.

Phenomenon based on the transverse thermoelectric (TE) effect occurs by tilting the materials with anisotropic TE properties. For obtaining artificially the anisotropic TE materials, combining TE material and metal with a specific structure is a promising method. In this review, the Ni/Mg₂Si composites with two kinds of specific structures were focused on. Influences of the structural conditions (volume fraction and tilt angle of Ni) on the TE properties of those composite elements were quantitatively analyzed using a finite element simulation (FES), and the optimum structural conditions bringing the maximum TE performance were predicted. Furthermore, power generation performances of two kinds of the modules constructed by the tilted Ni/Mg₂Si composite elements with the optimum structural conditions were estimated using FES.

Recently, additive manufacturing (AM) technology has been paid great attention in the aerospace, medical and automotive fields because of the possibility of manufacturing high-performance parts. In this paper, the new development of metal laser AM technology, especially the development of powder bed fusion type and deposition type AM machines, the analysis of melting-solidification phenomenon of melt pool, and the development of melting-solidification simulation, structure simulation and thermal deformation simulation are reviewed.

Commercially pure (CP) titanium and titanium alloy (Ti-6Al-4V) with a bimodal harmonic structure, which is defined as a coarse-grained structure surrounded by a network structure of fine grains, was fabricated using powder metallurgy to improve both the strength and ductility. Small fatigue crack propagation in bimodal harmonic structured titanium was examined by four-point bending under a stress ratio of 0.1 in the ambient laboratory atmosphere. The crack profiles were observed using optical microscopy and scanning electron microscopy (SEM), and analyzed using an electron backscattered diffraction (EBSD) to examine the mechanism of small fatigue crack propagation on the basis of fractography and crystallography. Fatigue crack paths were not influenced by the bimodal harmonic structure, and the crack growth rates, da/dN, in the harmonic structured titanium were almost the same as those in a material with coarse microstructure for comparable values of stress intensity range, ΔK. In contrast, the harmonic structured titanium had a higher resistance of fatigue crack initiation due to the grain refinement induced by mechanical milling, which resulted in an increase of the fatigue life and fatigue limit. Furthermore, an EBSD analysis was conducted on the facets observed on the fracture surfaces of the harmonic structured titanium to determine the microstructure near the crack initiation site. A transgranular fatigue crack was initiated in the α-facet of coarse-grained structure of the harmonic structured titanium.