A small specimen test technique is required to evaluate the fracture toughness values of several millimeter thick plates of structural materials and to maximize the use of very limited space for materials irradiation in intense neutron sources like IFMIF. In view of several advantages of three-point bending (3PB) over compact tension (CT), miniaturized 3PB specimens with 7.0, 5.0 and 3.3 mm thickness were prepared from a Japanese low activation ferritic steel, JLF-1, which is a candidate first wall and fusion blanket material.Elastic-plastic fracture toughness tests by the unloading compliance method at room temperature and plane-strain fracture toughness tests at 77 K were conducted in general accordance with the ASTM standards. Emphasis was focused on the determination of the actual J-value for crack initiation, J_IN, for reliable fracture toughness evaluation with the 3PB specimens. The obtained values of J_IN at room temperature and K_IC at 77 K were 100—120 kJ/m² and 20—22 MPam^1/2, respectively, exhibiting little dependence on specimen size. By combining the experimentally obtained data with the plane-strain FEM analysis, a method was proposed to estimate J_IN from a load-displacement curve measured for a single specimen. The method is applicable to heavily irradiated materials with little ductility.

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Microwave plasma was employed for the nitriding of SCM445 steel and characteristics of the steel obtained by this process were compared with those of steel treated by conventional ion nitriding. The latter showed a large amount of globular shaped nitride compounds around 1-2 μm size precipitated on the steel surface and surface coarsening after ion nitriding. However, microwave plasma nitriding successfully produced a nitrided steel without a compound layer and a diffusion layer thickness of more than 0.5 mm was achieved at gas composition of 30%N₂-70%H₂ (500°C, 2 h). Also, a smooth surface was also achieved. Microwave plasma nitriding was capable of producing just the diffusion layer with a good surface condition for subsequent deposition of a protective coating.

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Porcelain veneered on pure titanium with an intermediate plasma-sprayed ZrO₂ bond coat layer was investigated in this study. The pure porcelain coating veneered on Ti was used as a control. The specimens were subjected to four-point bending test to measure the bonding strength. The fractograph, microstructure, surface roughness, and phase of plasma-sprayed ZrO₂ bond coat were examined. The phase constituents at the location of adhesive failure of the fractured specimens were investigated by thin-film X-ray diffractometry. Experimental results reveal that the bonding strength of the coating with the intermediate layer was increased by 55.7% that was accompanied by a significant decrease of the area of adhesive failure in the fracture. The ZrO₂ provided a higher surface roughness to enhance the mechanical bond at the interface of porcelain/ZrO₂, meanwhile it acted as a sufficient oxygen diffusion barrier at 800°C to prevent the oxidation of Ti at the interface of ZrO₂/Ti.

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We have first calculated the driving force of ω phase transformation (PT) based on the electron-phonon interaction Hamiltonian. The nucleation rate of PT has also been investigated in the interaction system. The condensation of one single phonon makes a great contribution to the formation of charge density wave (CDW) whose amplitude is related to the wavevector of phonon. Considering the electron-phonon interaction and the condensation of phonon, Double Sine-Gordon equation of atomic phase angle has been proposed to study the nonlinear characteristics of ω PT and the electron-phonon coupling mechanism is suggested as the main mechanism of nucleation.

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A series of tensile testing was carried out on the ultrafine grained 5083 Al alloy, which was fabricated by equal channel angular pressing (ECAP) with different ECAP strains, at low temperature superplastic (LTS) temperature of 548 K. This investigation was aimed at examining the effect of the ECAP strain inducing different microstructure in the alloy on the deformation mechanisms at LTS regime. The most distinguishable microstructural evolution by increasing the ECAP strain from ∼4 to ∼8 was an increment of a portion of high angle boundaries while the (sub)grain size remained almost unchanged. The sample after 4 passes (a strain of ∼4) did not exhibit LTS, but superplastic elongations were obtained in the sample after 8 passes (a strain of ∼8). An analysis of the mechanical data in light of the standard deformation mechanisms revealed that deformation of the sample after 4 passes was governed by dislocation climb while grain boundary sliding attributed to LTS of the sample after 8 passes. The difference of the deformation mechanisms in the present case was discussed in terms of the microstructures developed under different ECAP strains.

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The synthesis of Au/TiO₂ core-shell structure nanoparticles was carried out by the hydrolysis of TOAA (titanium oxide acethylacetonate) in gold sol ethanol solution with water. It was possible to achieve 1 nm thick TiO₂ shell on the surface of gold particles. The morphology and the crystallinity of TiO₂ shell were investigated by TEM and UV-vis absorption spectrometer. The crystral structure of TiO₂ shell was amorphous because the surface plasmon band of gold nanoparticles appeared only when the radioactive ray was irradiated on the TiO₂-coated gold sol ethanol solution.

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Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and chemical analyses were used for characterizing the effect of sulfate ions on the conversion rate of condensed Fe(OH)₃ gel, prepared from FeCl₃ and NaOH solution, to β-FeOOH and α-Fe₂O₃ particles by aging at 100°C. Fine particles and supernatant solution were sampled from the aged suspensions containing colloidal particles. XRD profiles and TEM observation showed that β-FeOOH was formed from the gel and subsequently converted into α-Fe₂O₃. It was revealed that the addition of sulfate ions accelerated the β-FeOOH formation from the gel, but delayed the conversion from β-FeOOH to α-Fe₂O₃. The concentration changes of sulfate and chloride ions in the supernatant solution phases were in agreement with the conversion from Fe(OH)₃ gel to β-FeOOH and α-Fe₂O₃ particles.

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Assimilating the solid-liquid interface to a binary domain described by a set of coupled equations, one studies the solidification process. The numerical solutions of the thermal breather, the thermal breather pair and the thermal cluster type are associated to a virtual crystallization germ, a stable crystallization germ and a crystalline grain, respectively. The fractal characteristics of the solidification process are analyzed by means of fractal dimension dynamics.

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