Development of 9Cr-ODS Martensitic Steel Claddings for Fuel Pins by means of Ferrite to Austenite Phase Transformation.

Ukai, Shigeharu; Mizuta, S; Fujiwara, Masayuki; Okuda, Takanari; Kobayashi, Toshimi

doi:10.3327/jnst.39.778

Cited by 73 publications

(82 citation statements)

References 16 publications

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“…9Cr-1Mo steel, PNC-FMS and so on. 1,2) It is widely recognized that these desirable properties are attributable to nano-size Y-Ti-O complex oxide particles dispersed in the matrix which act as obstacles to movement of dislocations. A high density of nano-size YTi-O complex oxide particles is produced by mechanically alloying (MA) Fe-Cr-Ti powders with Y 2 O 3 followed by hot-solidification process.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Approach for Growth and Coalescence of Nano-Size Oxide Particles in 9Cr-ODS Steel Using High-Energy Synchrotron Radiation X-rays in SPring-8

et al. 2009

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Nanometer size oxide particles in 9Cr-ODS steel are dispersed finely and densely in a matrix by the hot-solidification process. The size and density distribution of dispersed oxide particles is recognized as one of the main issues for ensuring good microstructural stability and high temperature strength in a high temperature (<700 C) and neutron irradiation (250 dpa) environment. However, the behavior of oxide particles in the hot-solidification process has not been determined yet. This study evaluated the correlation between nano-size oxide particles and the heat treatment temperature and time in order to characterize the mechanism of formation and the behavior during growth and coalescence of these particles in 9Cr-ODS steel raw powder. XRD and SAXS measurements were made using high-energy synchrotron radiation X-rays in SPring-8. This is the first report of the oxide complex particles (Y 2 Ti 2 O 7 and Y 2 TiO 5 ) being formed from 800 to 960 C, and they were observed to grow and coalesce on increasing both heat-treatment temperature and time.

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Section: Introductionmentioning

confidence: 99%

Kinetic Approach for Growth and Coalescence of Nano-Size Oxide Particles in 9Cr-ODS Steel Using High-Energy Synchrotron Radiation X-rays in SPring-8

et al. 2009

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“…2,3) It was recently shown that microstructure and creep strength of 9CrODS steel is sensitive to subtle changes of oxygen and titanium concentrations. 3,4) To develop a consistently reliable manufacturing procedure for high strength 9CrODS steel, it is important to clarify the effects of manufacturing conditions on the mechanical properties of 9CrODS steel.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Creep Strength of 9CrODS Martensitic Steel by Controlling Excess Oxygen and Titanium Concentrations

Ohtsuka¹,

Ukai²,

Fujiwara³

et al. 2005

Mater. Trans.

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The effects of chemical compositions (titanium, oxygen) and consolidation temperature on high-temperature mechanical properties of 9Cr-oxide dispersion strengthened steel (9CrODS steel) were investigated. A possible high-temperature strengthening mechanism of 9CrODS steel was discussed based on the experimental results. Creep strength of 9CrODS steel at 973 K was remarkably improved when titanium concentration was 0.35 mass%. A higher amount of added titanium than 0.2 mass% was effective for providing consistently reliable manufacturing of high strength 9CrODS steel because it reduced the effect of oxygen contamination on high-temperature strength. The fraction of elongated -ferrite grains, which had an ultra-fine oxide particle dispersion, tended to increase with increasing titanium. The elongated grains were considered to improve creep strength of 9CrODS steel. It was also found that creep strength was degraded by elevating the consolidation temperature from 1423 K to 1473 K.

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“…These powders were degassed in vacuum, sealed in mild-steel cans, and consolidated by hot extrusion at 1423 K. From these consolidated bars, tubes were manufactured by a six-pass warm rolling at 923-973 K for 1DS and 1DK, and a two-pass spiral cold rolling for M93, F94 and F95 with intermediate and final heat treatments. 3,4) The chemical compositions and heat treatment conditions of the ODS ferritic and martensitic steels are shown in Table 1.…”

Section: Methodsmentioning

confidence: 99%

Mechanical Behavior of Oxide Dispersion Strengthened Steels Irradiated in JOYO

Yamashita¹,

Yoshitake²,

Akasaka³

et al. 2005

Mater. Trans.

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Oxide dispersion strengthened (ODS) steels, which are candidate materials for water-cooled solid breeder blankets, were fabricated with several manufacturing parameters, and then irradiated in the experimental fast reactor JOYO to evaluate their irradiation behavior.Engineering stress strain curves of ODS steels irradiated at 673 K exhibited superior material response, i.e., increased tensile strength due to irradiation hardening and no loss of total elongation. Also, their temperature dependence of tensile properties indicated that degradation of the tensile properties at elevated temperature, which is closely related to phase stability during irradiation, could be avoided due to optimal combination of manufacturing parameters, such as chemical composition, types of inert gas during mechanical alloying, heat-treatment temperature and initial phases of the matrix.

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Development of 9Cr-ODS Martensitic Steel Claddings for Fuel Pins by means of Ferrite to Austenite Phase Transformation.

Cited by 73 publications

References 16 publications

Kinetic Approach for Growth and Coalescence of Nano-Size Oxide Particles in 9Cr-ODS Steel Using High-Energy Synchrotron Radiation X-rays in SPring-8

Kinetic Approach for Growth and Coalescence of Nano-Size Oxide Particles in 9Cr-ODS Steel Using High-Energy Synchrotron Radiation X-rays in SPring-8

Improvement of Creep Strength of 9CrODS Martensitic Steel by Controlling Excess Oxygen and Titanium Concentrations

Mechanical Behavior of Oxide Dispersion Strengthened Steels Irradiated in JOYO

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