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Highlights: [•] Aluminum addition to ODS steel improves compatibility between U-Zr fuel and the ODS steels. [•] It increases the threshold temperature for reaction layer formation by 50K. [•] The compatibility improvement mechanism was discussed using general thermodynamic data. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective cohort analysis. Objective: To determine the effect of biological agents (BAs) on the development and progression of cervical spine lesions and identify predictors of lesion progression. Summary Of Background Data: The introduction of BAs has facilitated advances in the treatment of rheumatoid arthritis (RA). BAs reduce disease activity and limit structural joint damage. However, the effect of BAs on cervical spine lesions remains unclear. Methods: Thirty-eight subjects who received more than 2 years of continuous BA treatment were enrolled. The mean x-ray interval was 4.4 years. RA activity was evaluated by disease activity score (DAS)-C reactive protein (CRP) and matrix metalloproteinase (MMP)-3. Radiographical definitions of cervical lesions were atlanto-dental interval (ADI) more than 3 mm for atlanto-axial subluxation (AAS), Ranawat value less than 13 mm for vertical subluxation (VS), and anterior or posterior listhesis more than 2 mm for subaxial subluxation (SS). Definitions of radiographical progression were an increase of ADI more than 2 mm for AAS, a decrease of both Ranawat and Redlund-Johnell values more than 2 mm for VS, and an increase of listhesis more than 2 mm for SS. Results: RA activity responded dramatically to BA therapy (DAS-CRP from 4.3 to 2.3, P < 0.01; MMP-3 from 207.9 ng/mL to 105.6 ng/mL, P < 0.01). Baseline radiographical evaluation showed no pre-existing cervical spine lesions in 12 cases, AAS in 15 cases, and VS in 11 cases. Radiological progression was found in 1 (8%) patient in the no lesion group, 12 patients (80%) in the AAS group, and 9 patients (80%) in the VS group. The incidence of progression was significantly lower in the no lesion group compared with the other groups. Multivariate regression analysis showed that the presence of pre-existing cervical lesions was the single greatest predictor of progression. Conclusion: BAs prevented the development of de novo cervical spine lesions in patients with RA, but failed to inhibit progression of pre-existing RA lesions. [ABSTRACT FROM AUTHOR]

Abstract: This paper discusses the effects of small amount of Al contamination (<0.1wt%) on high-temperature strength and microstructure of the 9Cr–ODS steel. Increasing Al concentration degraded the ultimate tensile strength as well as the 0.2% proof stress at 973K and 1073K accompanied by decreasing fraction of the elongated grain, i.e., residual-α ferrite acting as reinforcement phase. The decrease of residual-α ferrite proportion provided by increasing Al is contrary to general behavior of conventional steels. Computer simulation on ferrite to austenite phase transformation suggested that the fine oxide dispersion in the elongated ferrite could be attributable to the preferential partitioning of Ti and W in ferrite than in austenite at hot-extrusion process. [Copyright &y& Elsevier]

Abstract: In order to examine irradiation effect on creep rupture strength of Oxide Dispersion Strengthened (ODS) steel claddings, the in-pile creep rupture test was conducted using Material Testing Rig with Temperature Control (MARICO)-2 in the experimental fast reactor JOYO. Fourteen creep rupture events were successfully detected by the temperature change in each capsule and the gamma-ray spectrometry of the cover gas. Time to creep ruptures of six ODS steel specimens were identified by means of Laser Resonance Ionization Mass Spectrometry (RIMS), and no irradiation effect on creep rupture strength was confirmed within the irradiation condition in the MARICO-2 test. [Copyright &y& Elsevier]

Oxide dispersion strengthened (ODS) steels are being developing for application as advanced fast reactor cladding and fusion blanket materials, in order to allow increased operation temperature. Oxidation testing of ODS steel was conducted under a controlled dry air atmosphere to evaluate the high temperature oxidation behavior. This showed that 9Cr-ODS martensitic steels and 12Cr-ODS ferritic steels have superior high temperature oxidation resistance compared to 11 mass% Cr PNC-FMS and 17 mass% Cr ferritic stainless steel. This high temperature resistance is attributed to earlier formation of the protective α-Cr2O3 on the outer surface of ODS steels. [Copyright &y& Elsevier]

Abstract: We have studied optical properties of near-infrared (NIR) spectra and birefringence of the manganese phthalocyanine (MnPc) thin films. The morphology of the MnPc thin film grown on KCl (001) substrates was observed by using an atomic force microscope. The NIR spectral range of 1.0–1.7μm was studied in this study, because that of 1.3–1.5μm is known as an optical communication wavelength. The birefringence was measured with changing the growth condition of a deposition rate and a substrate temperature. The birefringence of the film was most affected by the deposition rate. [Copyright &y& Elsevier]

Abstract: 11-12Cr oxide dispersion strengthened (ODS) tempered martensitic steels underwent manufacturing tests and their ferritic–martensitic duplex structures were quantitatively evaluated by three methods: high-temperature X-ray diffraction (XRD), electron probe microanalyzer (EPMA), and metallography. It was demonstrated that excessive formation of residual-α ferrite, due to increasing Cr content, could be suppressed by appropriately controlling the concentration of the ferrite-forming and austenite-forming elements on the basis of the parameter “chemical driving force of α to γ reverse transformation. 11Cr-ODS steel containing a small portion of residual-α ferrite was successfully manufactured. In the as-received condition, this 11Cr-ODS steel was shown to have satisfactory creep strength and ductility, both as high as those of the 9Cr-ODS steel, while its 0.2% proof strength at 973K was lower than in the 9Cr-ODS steel. [Copyright &y& Elsevier]

Abstract: PbBr2 single crystals were grown by a vertical Bridgman method. The objective of this work is to examine the following two: (i) how the crystal quality is influenced by purification, (ii) how the crystal quality is influenced by growth rate. The following results were obtained. (1) The crystals grown from the materials of 99.99% and 99.999% purity were not transparent if they were not purified. On the other hand, a transparent crystal was obtained even from the material of 99.99% purity when it was refined by directional freezing as well as vacuum distillation. (2) It was found that very slow growth rate was needed to grow transparent crystals. [Copyright &y& Elsevier]

We investigated the stability of oxide nano particles in oxide dispersion-strengthened (ODS) steel, which is a promising candidate material for next-generation reactors, under neutron irradiation at high temperature to high doses. MA957, a 14Cr-ODS steel, was irradiated with Joyo in Japan Atomic Energy Agency under irradiation conditions of 130 dpa at 502 ºC, 154 dpa at 589 ºC, and 158 dpa at 709 ºC. Three-dimensional atom probe (3D-AP) and transmission electron microscope (TEM) observation were performed to characterize the oxide particles in the ODS steels. A high number density of Y-Ti-O particle was observed in the unirradiated and irradiated samples. Almost no change in the morphology of the oxide particles, i.e. average diameter, number density, and chemical composition, has been observed in the samples irradiated to 130 dpa at 502 ºC and to 154 dpa at 589 ºC. A slight decrease in number density was observed in the sample irradiated to 158 dpa at 709 ºC. The hardness of any of the irradiated samples was almost unchanged from that of the unirradiated sample. It was revealed that the oxide particles existed stable, and the strength of the material was sufficiently maintained even after being neutron irradiated to high dose of ∼160 dpa at high temperature up to 700 ºC. Atom maps for Yttrium, Titanium and Oxygen in ODS steel before/after neutron irradiation obtained with three-dimensional atom probe. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Oxide dispersion strengthened (ODS) ferritic steels, which are the most promising candidate materials for advanced fast reactor fuel elements, have exceptional creep strength at 973K. The superior creep property of 9Cr-ODS ferritic steels is ascribed to the formation of a nonequilibrium phase, designated as the residual ferrite. The yield strength of the residual ferrite itself has been determined to be as high as 1360MPa at room temperature from nanoindentation measurements. The creep strength is also enhanced by minimizing the number of packet boundaries induced by the martensitic phase transformation. The creep strain occurs at a lower stress than that necessary for the deformation of the intragrain regions, which are strengthened by an interaction between nanosize oxide particles and dislocations; this occurs by sliding at weaker regions such as at the grain boundaries and packet boundaries. It is found that 9Cr-ODS ferritic steels behave as fiber composite materials comprising the harder residual ferrite and the softer tempered martensite. [Copyright &y& Elsevier]

Abstract 9Cr-ODS steel claddings consisting of tempered martensitic matrix, showed prominent creep rupture strength at 1000 °C, which surpassed that of heat-resistant austenitic steels although creep rupture strength of tempered martensitic steels is generally lower than that of austenitic steels at high temperatures. The measured creep rupture strength of 9Cr-ODS steel claddings at 1000 °C was higher than that from extrapolated creep rupture trend curves formulated using data at temperatures from 650 to 850 °C. This superior strength seemed to be owing to transformation of the matrix from the α-phase to the γ-phase. The transient burst strengths for 9Cr-ODS steel were much higher than those for 11Cr-ferritic/martensitic steel (PNC-FMS). Cumulative damage fraction analyses suggested that the life fraction rule can be used for the rupture life prediction of 9Cr-ODS steel and PNC-FMS claddings in the transient and accidental events with a certain accuracy. [ABSTRACT FROM AUTHOR]

The growth of oxide particles in FeCrAl- oxide dispersion strengthened steel (ODSS) considering an accident condition of the light-water reactor at above 1500 K was studied by using a high-temperature annealing. Oxide particles grew from 9 nm to more than 50 nm as maximum at 1623 K for 27 h, with decreasing their number density in two orders of magnitude. Most of the oxide particles in 15Cr-7Al were identified as YAM or YAP, while the oxide particles in 15Cr-7Al-0.4Zr were identified trigonal Y 4 Zr 3 O 12 . Zr addition to 15Cr-7Al ODSS accelerated the growth of the oxide particles, which is quite contrary to the effect of Zr addition during sintering as suggested in the literature. The kinetics of coarsening was characterized by an equation of Ostwald ripening. The diffusion activation energies obtained in the present materials were quite larger than the conventional diffusion activation energy of Y in alpha-iron. Gibbs free energy of oxides should be considered to discuss the coarsening. [ABSTRACT FROM AUTHOR]

Ultra-high temperature ring tensile tests were performed to investigate the tensile behavior of oxide dispersion strengthened (ODS) steel claddings and wrapper materials under severe accident conditions with temperatures ranging from room temperature to 1400 °C which is close to the melting point of core materials. The experimental results showed that the tensile strength of 9Cr-ODS steel claddings was highest in the core materials at ultra-high temperatures of 900 – 1200 °C, but there was significant degradation in the tensile strength of 9Cr-ODS steel claddings above 1200 °C. This degradation was attributed to grain boundary sliding deformation with γ/δ transformation, which is associated with reduced ductility. By contrast, the tensile strength of recrystallized 12Cr-ODS and FeCrAl-ODS steel claddings retained its high value above 1200 °C, unlike the other tested materials. [ABSTRACT FROM AUTHOR]

Increasing Cr content from 9 to 12 mass% leads to superior corrosion and high-temperature oxidation resistances, and usually changes microstructure from martensite to a ferrite. To make transformable martensitic type of 12CrODS steels that have superior processing capability by using α/γ phase transformation, alloy design was conducted through varying nickel content. The structure of 12CrODS steels was successfully modified from full ferrite to a transformable martensite-base matrix containing ferrite. This ferrite consists of both equilibrium ferrite and a metastable residual ferrite. It was shown that the fraction of the equilibrium ferrite is predictable by computed phase diagram and formation of the residual ferrite was successfully evaluated through pinning of α/γ interfacial boundaries by oxide particles. [ABSTRACT FROM AUTHOR]

Abstract: The 9CrODS steel specimens were prepared by different processing with hot-rolling and different cooling rate. The hardness and high-temperature tensile properties were measured. Microstructure was analyzed by means of EBSD inverse pole figure and kernel average miss-orientation angles. The hot-rolled and then air-cooled specimen has the highest tensile strength. The furnace-cooled specimen also has better tensile strength at 700°C than air-cooled specimen at normalized condition. The high-temperature strength of 9CrODS steel is significantly improved with increasing grain size that can be induced by hot-rolling or furnace-slow cooling, where the localized grain boundary deformation can be suppressed. [Copyright &y& Elsevier]

Abstract: The effects of fast neutron irradiation on ring tensile properties of oxide dispersion strengthened (ODS) steel claddings for fast reactor were investigated. Specimens were irradiated in the experimental fast reactor Joyo using the material irradiation rig at temperatures between 693 and 1108K to fast neutron doses ranging from 16 to 33dpa. The post-irradiation ring tensile tests were carried out at irradiation temperatures. The experimental results showed that there was no significant change in tensile strengths after neutron irradiation below 923K, but the tensile strengths at neutron irradiation above 1023K up to 33dpa were decreased by about 20%. On the other hand, uniform elongation after irradiation was more than 2% at all irradiation conditions. The ring tensile properties of these ODS claddings remained excellent within these irradiation conditions compared with conventional 11Cr ferritic/martensitic steel (PNC-FMS) claddings. [Copyright &y& Elsevier]

Abstract: It is recognized that the high-temperature strength of 9Cr-ODS ferritic steels is maintained by the presence of a ferrite phase. In order to clarify the formation process of the ferrite phase, 9Cr-ODS ferritic steels containing various contents of Y2O3, i.e., 0mass%, 0.1mass%, 0.35mass%, and 0.7mass%, are prepared by means of mechanical alloying and hot-pressing. The ferrite phase is formed by the addition of 0.35mass% and 0.7mass% Y2O3; however, it is not formed for steels without and with 0.1mass% Y2O3 normalized for 1h at 1050°C. It is considered from the thermodynamic analyses that the pinning of the α–γ interface motion by the dispersed Y–Ti complex oxide particles can be attributed to the retention of the ferrite phase normalized at 1050°C, and this ferrite phase cannot be δ-ferrite that is in equilibrium with the γ-phase. [Copyright &y& Elsevier]

Abstract: The size and number density of oxide nanoparticles in 9Cr-oxide dispersion strengthened (ODS) steels with different concentrations of excess O, Ti and W are quantitatively determined using small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS). Based on the difference of the SANS and SAXS intensity in absolute units, the “alloy contrast variation (ACV) method” has been used to determine the compositions of the oxide nanoprecipitates. The results indicate that the finest size and highest number density of oxide nanoparticles is obtained by suppressing the amount of excess O and increasing the amount of Ti. The ACV method indicates that the finest oxide nanoparticles have a chemical composition close to Y2Ti2O7. [Copyright &y& Elsevier]

Abstract: This paper describes the effect on creep strength and microstructure of 9Cr-oxide dispersion strengthened martensitic steel (9Cr-ODS steel) produced by differences in titanium concentration and consolidation temperature. The increase of titanium concentration to 0.30–0.35wt% was shown to provide considerable improvement of creep strength accompanied by the increase of residual-α ferrite. The elevation of hot-extrusion temperature degraded the creep strength, however, it appeared to increase the volume fraction of residual-α ferrite. The creep deformation process of 9Cr-ODS steel was discussed to explain these results based on microstructure observations. [Copyright &y& Elsevier]

Abstract: The effects of mechanical alloying (MA) conditions on oxygen contamination were investigated to establish the manufacturing technology of oxygen-controlled oxide dispersion strengthened (ODS) martensitic steel. High-temperature mechanical tests and microstructure observations were performed in oxygen-and-titanium-controlled steels in order to demonstrate high-temperature strength improvement using oxygen control. Oxygen content was drastically reduced by the purification of MA atmosphere, Ar gas. It was shown that the lower speed agitation at the beginning of MA was effective for the reduction of oxygen contamination because oxygen was mixed mainly at the beginning of mechanical alloying due to the imperfect replacement of Ar gas. Dense distribution of oxide particle and significant improvement in high-temperature strength were achieved by applying 99.9999wt% Ar in MA atmosphere and reducing oxygen contents. It was revealed that the merely increasing Y2O3 and titanium addition cannot improve the high-temperature strength. The excess oxygen is an important parameter for making oxide particles finely and densely distributed as well as improving high-temperature strength. [Copyright &y& Elsevier]

Welding technology between 9Cr-ODS martensitic cladding and end-plugs has been developed by means of the pressurized resistance welding (PRW) method under solid state condition. The method is based on electrical resistance heating of the components while maintaining a continuous force sufficient to forge weld without melting. The appropriate conditions, e.g., electric current, voltage and contact force, were selected. For the PRW welded specimens, the tensile, internal burst and creep rupture tests were conducted and its integrity was confirmed. In addition, a non-destructive ultrasonic inspection method has been developed to assure the integrity of the weld between cladding and end-plug. The PRW was conducted to fabricate the ODS fuel pins in a JNC-Russia collaboration work, and the integrity accomplishment of the welded parts was verified through dimensional and leak testing, mechanical testing and micrographic examination. [Copyright &y& Elsevier]

The effects of different percentages of oxygen and titanium on the mechanical properties and microstructure of 9Cr-ODS steel were investigated. It was shown that the high-temperature strength was drastically improved by controlling the atomic ratio between excess oxygen and titanium (x in TiOx) around 1.0. When x is around 1.0, the elongated alpha-grains containing the ultra-fine and close oxide particle dispersion were generated in addition to equiaxed martensite grains. Furthermore, the number density of oxide particle in the martensite grains increased. The control of phase transformation and oxide particle dispersion by adjusting oxygen and titanium contents should be a key technology to achieve superior high-temperature strength. [Copyright &y& Elsevier]

This paper reviewed recent results on three-dimensional nano-structures fabrication techniques using focused-ion-beam induced chemical vapor deposition (FIB-CVD). Precise control of beam scanning and the source-gas pressure enabled the lateral growth of amorphous carbon, and we demonstrated real three-dimensional growth of amorphous carbon objects such as wineglasses, coils and micro-crowns. The major advantage of such amorphous carbon objects are their high Young’s modulus exceeding 600 GPa. The Young’s modulus depended sensitively on the growth rate, where slower growth rate resulted in higher stiffness. [Copyright &y& Elsevier]

Abstract: The aim of this paper is to fabricate the planar type patch clamp ion-channel biosensor, which is suitable for the high throughput screening, using silicon-on-insulator (SOI) substrate. The micropore with 1.2 μm diameter is formed through the top Si layer and the SiO2 box layer of the SOI substrate by focused ion beam (FIB). Then the substrate is assembled into the microfluidic circuit. The human embryonic kidney 293 (HEK-293) cell transfected with transient receptor potential vanilloid type 1 (TRPV1) is positioned on the micropore and the whole-cell configuration is formed by the suction. Capsaicin is added to the extracellular solution as a ligand molecule, and the channel current showing the desensitization unique to TRPV1 is measured successfully. [Copyright &y& Elsevier]

Abstract: Friction stir welding was applied to the wrapper tube materials, 11Cr-ferritic/martensitic steel, designed for fast reactors and defect-free welds were successfully produced. The mechanical and microstructural properties of the friction stir welded steel were subsequently investigated. The hardness values of the stir zone were approximately 550Hv (5.4GPa) with minimal dependence on the rotational speed, even though they were much higher than those of the base material. However, tensile strengths and elongations of the stir zones were high at 298K, compared to those of the base material. The excellent tensile properties are attributable to the fine grain formation during friction stir welding. [Copyright &y& Elsevier]

Abstract: The microstructure and tensile properties at 973K in 9CrODS steels were investigated with respect to various fractions of the residual ferrite from zero to 47vol.%. The formation of the residual ferrite was discussed from a balance between a chemical driving force for α to γ reverse transformation and the oxide particle pinning force, while 0.04mass% carbon sample could contain an equilibrium δ-ferrite. With increasing volume fraction of the residual ferrite, strength at 973K increases but ductility decreases, which is attributed to the fact that the residual ferrite is harder than the tempered martensite. [Copyright &y& Elsevier]