Nano-mesoscopic structural characterization of 9Cr-ODS martensitic steel for improving creep strength

Ohtsuka, Satoshi; Ukai, Shigeharu; Sakasegawa, Hideo; Fujiwara, Masayuki; Kaito, Takeji; Narita, Takeshi

doi:10.1016/j.jnucmat.2007.03.004

Cited by 62 publications

(24 citation statements)

References 12 publications

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“…23,24 Compared with MA-HIP ODS 304 the ODS LM specimens show higher yield strength and much higher ductility. More homogenous dispersion of oxide nanoinclusions and no contamination involved in ODS LM are believed to be the reasons behind this improvement.…”

Section: Resultsmentioning

confidence: 99%

Austenitic stainless steel strengthened by the in situ formation of oxide nanoinclusions

et al. 2015

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An austenitic stainless steel was prepared by laser melting. High resolution transmission electron microscopy with energy dispersive spectrometry confirmed the in situ formation of oxide nanoinclusions with average size less than 50 nm. Scanning electron microscopy examination revealed the homogeneous dispersion of the oxide nanoinclusions in the steel matrix. The tensile and yield strengths of the prepared specimens were 703 and 456 MPa respectively with high ductility which is significantly improved compared to its conventionally casted counterpart.

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Section: Resultsmentioning

confidence: 99%

Austenitic stainless steel strengthened by the in situ formation of oxide nanoinclusions

et al. 2015

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“…For transformable 9CrODS steels, it is known that their structure is a dual phase composed of tempered martensite and ferrite [4][5][6], although the full-tempered martensite is predicted in the equilibrium phase diagram. This ferrite is designated as a metastable residual ferrite, and it is also known that the residual ferrite significantly improves the high-temperature strength in 9CrODS steels [7][8][9][10][11][12]. The structure of martensitic base 12CrODS steels is, therefore, investigated, focusing on residual ferrite formation improving high-temperature strength.…”

Section: Introductionmentioning

confidence: 99%

Residual ferrite formation in 12CrODS steels

Ukai

Kudo

et al. 2014

Journal of Nuclear Materials

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Increasing Cr content from 9 to 12 mass % leads to superior corrosion and high-temperature oxidation resistances, but usually changes microstructure from martensite to full-ferrite. Alloy design was conducted for 12CrODS steels to modify their structure to the martensite-base matrix, since the transformable martensititic ODS steels have superior processing capability by using α/γ phase transformation. The two types of ferrite are included; the equilibrium ferrite is predictable from the equilibrium phase diagram. Formation of the metastable residual ferrite was assessed through pinning of α/γ interfacial boundaries by oxide particles as well as chemical driving force for the α to γ transformation.

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“…The ODS ferritic/martensitic steels are also expected as advanced heat-resistant steels for a next generation fossil power plant with extremely high thermal efficiency, toward reducing CO2 emission. There are two types of ODS ferritic/martensitic steels; one is 9CrODS martensite steel which has grain structure controlled by a reversible α/γ phase transformation, [1][2][3][4] the other is 12-15CrODS ferritic steel which has a recrystallized structure.…”

Section: Introductionmentioning

confidence: 99%

Grain Boundary Deformation at High Temperature Tensile Tests in ODS Ferritic Steel

et al. 2011

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The tensile test of the recrystallized ODS ferritic steels was performed in the loading direction for the longitudinal and 45° inclined with respect to the grains alignment. The testing temperature was 800°C and the strain rate was 10 -4 s -1 . A clear serration structure was observed at near the grain boundaries at the surface of 45° specimen ruptured. This is a clear evidence of the occurrence of the grain boundary sliding in 45° direction. For the total strain of 12% in 45° direction, grain boundary deformation induced by sliding was estimated about 9%, whereas the amounts of the transgranular strains was 2% measured by EBSD analysis. The grain-subdivision was also identified near grain boundaries by FIB analysis, which could be caused by a dynamic recrystallization during the localized grain boundary deformation.

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Nano-mesoscopic structural characterization of 9Cr-ODS martensitic steel for improving creep strength

Cited by 62 publications

References 12 publications

Austenitic stainless steel strengthened by the in situ formation of oxide nanoinclusions

Austenitic stainless steel strengthened by the in situ formation of oxide nanoinclusions

Residual ferrite formation in 12CrODS steels

Grain Boundary Deformation at High Temperature Tensile Tests in ODS Ferritic Steel

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