A variety of composite powders having different aluminum and carbon contents are prepared using various organic solvents having different amounts of carbon atoms in unit volume as ball milling agents for titanium and aluminum ball milling. The effects of substrate temperature and post-heat treatment on the texture and hardness of the coating are investigated by spraying with this reduced pressure plasma spray. The aluminum part of the composite powder evaporates during spraying, so that the film aluminum content is 30.9 mass%~37.4 mass% and the carbon content is 0.64 mass%~1.69 mass%. The main constituent phase of the coating formed on the water-cooled substrate is a non-planar α2 phase, obtained by supersaturated carbon regardless of the alloy composition. When these films are heat-treated at 1123 K, the main constituent phase becomes  phase, and fine Ti2AlC precipitates to increase the film hardness. However, when heat treatment is performed at a higher temperature, the hardness is lowered. The main constitutional phase of the coating formed on the preheated substrate is an equilibrium gamma phase, and fine Ti2AlC precipitates. The hardness of this coating is much higher than the hardness of the coating in the sprayed state formed on the water-cooled substrate. When hot pressing is applied to the coating, the porosity decreases but hardness also decreases because Ti2AlC grows. The amount of Ti2AlC in the hot-pressed film is 4.9 vol% to 15.3 vol%, depending on the carbon content of the film.

In this study, factors considered to be causes of promotion of densification of sintered pellets identified during phase change are reviewed. As a result, conclusions shown below are obtained for each factor. In order for MA powder to soften, a temperature of 1,000 K or higher is required. In order to confirm the temporary increase in density throughout the sintered pellet, the temperature rise due to heat during phase change was found not to have a significant effect. While examining the thermal expansion using the compressed powder, which stopped densification at a temperature below the MA powder itself, and the phase change temperature, no shrinkage phenomenon contributing to the promotion of densification is observed. The two types of powder made of Ti-silicide through heat treatment are densified only in the high temperature region of 1,000 K or more; it can be estimated that this is the effect of fine grain superplasticity. In the densification of the amorphous powder, the dependence of sintering pressure and the rate of temperature increase are shown. It is thought that the specific densification behavior identified during the phase change of the Ti-37.5 mol.%Si composition MA powder reviewed in this study is the result of the acceleration of the powder deformation by the phase change from non-equilibrium phase to equilibrium phase.

The composition of martensite transformation in NiAl alloy is determined using pure nickel and aluminum powder by vacuum hot press powder metallurgy, which is a composition of martensitic transformation, and the characteristics of martensitic transformation and microstructure of sintered NiAl alloys are investigated. The produced sintered alloys are presintered and hot pressed in vacuum; after homogenizing heat treatment at 1,273 K for 86.4 ks, they are water-cooled to produce NiAl sintered alloys having relative density of 99 % or more. As a result of observations of the microstructure of the sintered NiAl alloy specimens quenched in ice water after homogenization treatment at 1,273 K, it is found that specimens of all compositions consisted of two phases and voids. In addition, it is found that martensite transformation did not occur because surface fluctuation shapes did not appear inside the crystal grains with quenching at 1,273 K. As a result of examining the relationship between the density and composition after martensitic transformation of the sintered alloys, the density after transformation is found to have increased by about 1 % compared to before the transformation. As a result of examining the relationship between the hardness (Hv) at room temperature and the composition of the matrix phase and the martensite phase, the hardness of the martensite phase is found to be smaller than that of the matrix phase. As a result of examining the relationship between the temperature at which the shape recovery is completed by heating and the composition, the shape recovery temperature is found to decrease almost linearly as the Al concentration increases, and the gradient is about -160 K/ at% Al. After quenching the sintered NiAl alloys of the 37 at%Al into martensite, specimens fractured by three-point bending at room temperature are observed by SEM and, as a result, some grain boundary fractures are observed on the fracture surface, and mainly intergranular cleavage fractures.

In order to observe the microstructure and morphology of porous titanium -oxide thin film, deposition is performed under a higher Ar gas pressure than is used in the general titanium thin film production method. Black titanium thin film is deposited on stainless steel wire and Cu thin plate at a pressure of about 12 Pa, but lustrous thin film is deposited at lower pressure. The black titanium thin film has a larger apparent thickness than that of the glossy thin film. As a result of scanning electron microscope observation, it is seen that the black thin film has an extremely porous structure and consists of a separated column with periodic step differences on the sides. In this configuration, due to the shadowing effect, the nuclei formed on the substrate periodically grow to form a step. The surface area of the black thin film on the Cu thin plate changes with the bias potential. It has been found that the bias of the small negative is effective in increasing the surface area of the black titanium thin film. These results suggest that porous titanium-oxide thin film can be fabricated by applying the appropriate oxidation process to black titanium thin film composed of separated columns.

Crystal structure of the L12 type (Al,X)3Ti alloy (X = Cr,Cu) is analyzed by X-ray diffractometry and the nonuniform strain behavior at high temperature is investigated. The lattice constants for the L12 type (Al,X)3Ti alloys decrease in the order of the atomic number of the substituted atom X, and the hardness tends to increase. In a compressive test at around 473K for Al67.5Ti25Cr7.5, Al65Ti25Cr10 and Al62.5Ti25Cu12.5 alloys, it is found that the stress-strain curves showed serration, and deformation rate dependence appeared. It is assumed that the generation of serration is due to dynamic strain aging caused by the diffusion of solute atoms. As a result, activation energy of 60-95 kJ/mol is obtained. This process does not require direct involvement. In order to investigate the generation of serrations in detail, compression tests are carried out under various conditions. As a result, in the strain rate range of this experiment, serration is found to occur after 470K at a certain critical strain. The critical strain increases as the strain rate increases at constant temperature, and the critical strain tends to decrease as temperature rises under constant strain rate. This tendency is common to all alloys produced. In the case of this alloy system, the serration at around 473K corresponds to the case in which the dislocation velocity is faster than the diffusion rate of interstitial solute atoms at low temperature.