Development of an extensive database of mechanical and physical properties for reduced-activation martensitic steel F82H

Jitsukawa, Shiro; Tamura, Manabu; Schaaf, B. van der; Klueh, R.L.; Alamo, A.; Petersen, C.; Schirra, M.; Spaetig, P.; Odette, G.R.; Tavassoli, A.A.; Shiba, K.; Kohyama, Akira; Kimura, Akihiko

doi:10.1016/s0022-3115(02)01075-9

Cited by 186 publications

(89 citation statements)

References 6 publications

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“…[10][11][12] However, creep behavior of the steel has not been clarified sufficiently, while structural steel should not be used in a strain range of acceleration creep. Therefore, the effect of secondary hardening on creep behavior of F82H should be studied further from the engineering viewpoint.…”

Section: Introductionmentioning

confidence: 99%

Creep Behavior of Double Tempered 8%Cr-2%WVTa Martensitic Steel

Tamura

Nowell²,

Shinozuka

et al. 2006

Mater. Trans.

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Creep testing was carried out at around 650 C for a martensitic 8Cr-2WVTa steel (F82H), which is a candidate alloy for the first wall of the fusion reactors of the Tokamak type. Rupture strength of the double tempered steel (F82HD) is lightly higher than that of simply tempered steel (F82HS). On the other hand, creep rate of F82HD is obviously smaller than that of F82HS in acceleration creep, though creep strain of F82HD in transition creep, where creep rate decreases with increasing strain, is larger than that of F82HS. Hardness of the crept F82HD decreases with increasing creep strain, which corresponded with the transmission electron microscopy (TEM) observation. On the contrary, X-ray diffraction and electron back-scattered diffraction pattern measurements show that fine sub-grains are created during transition creep. The creep curves were analyzed using an exponential type creep equation and the apparent activation energy, the activation volume and the pre-exponential factor were calculated as a function of creep strain. Then, these parameters were converted into two parameters, i.e. equivalent obstacle spacing (EOS) and mobile dislocation density parameter (MDDP). While EOS decreases with increasing creep strain, MDDP increases with increasing strain during transition creep. The decrease in EOS and the increase in either EOS or MDDP are rate-controlling factors in transition and acceleration creep, respectively. On the other hand, in case of F82HS, EOS increases and MDDP decreases during transition creep. In this case, the decrease in MDDP controls the creep rate during transition creep of F82HS. It is concluded that both EOS and MDDP are representative parameters of the change in substructure during creep.

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Section: Introductionmentioning

confidence: 99%

Creep Behavior of Double Tempered 8%Cr-2%WVTa Martensitic Steel

Tamura

Nowell²,

Shinozuka

et al. 2006

Mater. Trans.

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“…The chemical compositions and heat treatment conditions are listed in Table 1. 19,20) JLF-1 was developed by Japanese universities, while F82H was developed by the Japan Atomic Energy Research Institute and Japan Steel Engineering Holding, Inc. The microstructures of both of the steels are of tempered martensite.…”

Section: Introductionmentioning

confidence: 99%

Current Status of Reduced-Activation Ferritic/Martensitic Steels R&D for Fusion Energy

Kimura

2005

Mater. Trans.

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Reduced-activation ferritic/martensitic (RAF/M) steels have been considered to be the prime candidate for the fusion blanket structural material. The irradiation data obtained up to now indicates rather high feasibility of the steels for application to fusion reactors because of their high resistance to degradation of material performance caused by both the irradiation-induced displacement damage and transmutation helium atoms. The martensitic structure of RAF/M steels consists of a large number of lattice defects before the irradiation, which strongly retards the formation of displacement damage through absorption and annihilation of the point defects generated by irradiation. Transmutation helium can be also trapped at those defects in the martensitic structure so that the growth of helium bubbles at grain boundaries is suppressed. The major properties of the steels are well within our knowledge, and processing technologies are mostly developed for fusion application. RAF/M steels are now certainly ready to proceed to the next stage, that is, the construction of International Thermo-nuclear Experimental Reactor Test Blanket Modules (ITER-TBM).Oxide dispersion strengthening (ODS) steels have been developed for higher thermal efficiency of fusion power plants. Recent irradiation experiments indicated that the steels were quite highly resistant to neutron irradiation embrittlement, showing hardening accompanied by no loss of ductility. High-Cr ODS steels whose chromium concentration was in the range from 14 to 19 mass% showed high resistance to corrosion in supercritical pressurized water. It is shown that the 14Cr-ODS steel is susceptible to neither hydrogen nor helium embrittlement.A combined utilization of ODS steels with RAF/M steels will be effective to realize fusion power early at a reasonable thermal efficiency.

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“…In addition to requirements regarding chemical composition, mechanical and radiation damage properties must be taken into account for RA steels in view of the severe service conditions envisaged for them, these conditions including neutron irradiation up to 70 dpa (DEMO reactor), an operating temperature range of 250-550°C and a lifetime of 20 000 h. 1) Ferritic and martensitic RA steels have been investigated in European, USA, Japanese and international collaborative fusion materials programs. [2][3][4][5][6] The basic compositions of these steels, taken from Refs. 2), 7)-9), are summarized in Table 1.…”

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confidence: 99%

Thermodynamic Modeling in Reduced Activation Steels

Danón

Servant

2005

ISIJ Int.

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Reduced Activation (RA) martensitic steels of the 9/11CrWVTa type are promising candidates for fusion reactor applications as long as they exhibit good mechanical properties-similar to those of commercial martensitic steels of the 9/12CrMo(NbV) type-and satisfy design criteria related to the behavior under irradiation. A contribution on thermodynamic modeling in RA steels is presented. The current status of the development of a thermodynamic database in the framework of the CALPHAD approach is reported. Thermodynamic calculations concerning RA alloys are discussed which can be helpful to interpret experimental observations on phase relationships, phase compositions, transition temperatures, etc.

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Development of an extensive database of mechanical and physical properties for reduced-activation martensitic steel F82H

Cited by 186 publications

References 6 publications

Creep Behavior of Double Tempered 8%Cr-2%WVTa Martensitic Steel

Creep Behavior of Double Tempered 8%Cr-2%WVTa Martensitic Steel

Current Status of Reduced-Activation Ferritic/Martensitic Steels R&D for Fusion Energy

Thermodynamic Modeling in Reduced Activation Steels

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