Yielding and deformation behavior was overviewed for polycrystalline ferritic steels with various grain sizes and carbon contents. In the well-annealed ferritic steels, yielding is governed by the mechanism of grain refinement strengthening (GRS) and yield stress follows the Hall-Petch relation as to grain size. Conversely, yielding of cold rolled ferritic steels is governed by the mechanism of dislocation strengthening (DS) and yield stress follows the Bailey-Hirsch relation as to dislocation density. Under the same percentage of deformation, dislocation introduction is promoted with decreasing ferrite grain size and this results in higher yield stress (or flow stress) in specimens with smaller grain size. Yielding elongation appears due to the plastic instability that is realized during the change of strengthening mechanism from GRS to DS. Therefore, the extent of yielding elongation is determined in the relation between yield stress and work hardening behavior of matrix. Temper rolling plays a role to make the strengthening mechanism change from GRS to DS. When the extent of temper rolling is so small as about 1％, yield stress of temper rolled specimens is lowered below that of the as-annealed specimen. This is the reason why yield stress of the temper rolled specimen is lowered below that of as-annealed specimen. In the relation between GRS and DS, there is not additional but competitive relationship.

Ag nanoparticles were prepared by the arc plasma method with various conditions. The powder properties such as the particle size, its distribution, particle shape, and purity of those were investigated. It is revealed that an average particle size of the Ag nanoparticles decreases with increasing the arc current during the arc plasma method. Moreover, it is confirmed that the crystallite size measured using X-ray diffraction (XRD) was smaller than the average particle size, regardless of the arc current. Thus, it is concluded that the Ag nanoparticles prepared by this method are polycrystalline particles. No Ag oxides in the nanoparticles were recognized both by field emission scanning electron microscopy (FE-SEM) observations and XRD analysis. Moreover, the solid solution of oxygen in Ag was not measured by XRD and wavelength dispersive X-ray spectrometry (WDS) analysis.

Solidification of aluminum slab and cylindrical ingot induced by heat transfer was analyzed by tracing the flow of latent heat of fusion from liquid-solid interface to surface and therefrom to outside. Temperature drop at surface below melting point during solidification was found to be connected to the thickness of solid layer and heat transfer coefficient in respective modes of solidification. Relationship between the thickness of solid layer and temperature drop given by the above connection enabled to estimate the increasing rate in thickness of solid layer. Repetition of above calculations from the beginning resulted in solidification times of slab and cylindrical ingot with varied sizes and varied heat transfer coefficient. The solidification times thus obtained were shown in numerical tables for respective modes of solidification. Solidification of the superheated aluminum slab was analyzed by use of parabolic distribution of temperature in liquid before and during the solidification.

Cymbals are percussion musical instruments with a simpler structure than other musical instruments. Therefore, their material composition basically decides the sound quality and decay time rather than the skill of the player. In this study, specimens of cymbals to which Titanium, Zirconium and Iron were added were prepared. From the difference of diffraction rings by synchrotron radiation X-rays, the crystal structure of the specimens of cymbals prepared by various manufacturing processes was analyzed in order to investigate the relationship between the crystal structure associated with the material and manufacturing process used and the damping of the sound of cymbals. As a result, it was found that the changes in the crystal structure were due to the manufacturing process used. In addition, it was clarified that the changes affected the damping of the sound of cymbals.

Ti_1−x-Al_x-N-O powders, with Al content in metallic elements (x = x_Al/x_Ti + x_Al) ranging from 0 to 0.4, were synthesized from TiN and Al₂O₃ powders using mechanical alloying. Densification of these original powders is carried out by the spark plasma sintering is performed at 50 MPa and up to 1300℃. From the result of X-ray diffraction(XRD) and transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDS), it was confirmed that (Ti,Al)(N,O) phase with NaCl structure was synthesized from the Ti_1−x-Al_x-N-O powder with x = 0.2. However, XRD results indicated that crystal phase of sintered bodies was TiN-Al₂O₃ composite. The theoretical densities of sintered bodies were increase from 95.6％ to 99.6％ with increasing of x in the range from 0 to 0.4. Furthermore, the Ti_1−x-Al_x-N-O ceramics with x = 0.3 and 0.1 exhibited maximum Vickers hardness of HV2230 and maximum fracture toughness of 5.5 MPa·m^1/2, respectively.