He, P.

Lindau, R.

Möeslang, A.

Sandim, H.R.Z.

English

Sandim, H. R. Z.

KITopen

AbstractReduced activation oxide dispersion strengthened (ODS) ferritic steels are the most promising structural materials for future fusion power plants and innovative fissionnuclear reactors. The structure and mechanical properties of fine-grained 13.5% Cr ODS ferritic steels, processed by hot cross rolling to large strains of 70 % andsubsequent annealing have been investigated. The microstructure after hot cross rolling is partially recrystallized. The texture of the ODS ferritic steel after rolling andannealing has a sharp rotated cube ({100} <110>) texture component. The γ-fiber component (<111> // ND) typical of recrystallized rolled ferritic steels is absent. Similarvalues of tensile strength are obtained for rolled samples regardless the sample orientation in comparison with hot isostatically pressed samples whereas a substantialenhancement in total elongation (22 %) is present at 500 °C. Cross-rolled ODS steels represent an increase in upper shelf energy to 2 J compared with hot isostaticallypressed samples. The relatively poor toughness properties, compared to 9Cr ODS RAFM steel Eurofer-ODS, can be attributed mainly to the absence of the γ-fiber texturecomponent, bimodal grain size distribution and high amounts of interstitial impurities (O, N).P. Hea, R. Lindaua, A. Moeslanga, H.R.Z. Sandimba) b)Influence of the thermomechanical treatment on the mechanical propertiesof 13.5Cr ODS steelsInstitute for Applied MaterialsApplied Materials Physics (IAM-AWP)Hermann-von-Helmholtz-Platz 176344 Eggenstein-LeopoldshafenKarlsruhe, GermanyChemical composition and fabrication parameters of 13.5Cr ODS steelsMA: 24h (1000/4min+700/1min); H2; Ball-to-powder ratio=10:1HIP: 1150°C, 100MPa, 2.5 hours; TMT: Three passes cross rolling at 1100°C ( thickness reduction from 22 mm to 6 mm) ;  annealing at 1050 °C, 2 hoursTi alloyed, HIP0.30.31.113.5161/11Ti alloyed, HIP, for comparison0.00.31.113.5161/013Ti alloyed, as-rec., 1kg rect., HIP + rolling0.00.31.113.5161/314Ti alloyed, 1 kg, HIP + rolling0.30.31.113.5161/29RemarksY2O3TiWCrHeatCapsel-No.a - Institute for Applied Materials-Applied Materials Physics, Karlsruhe Institute of Technology, Karlsruhe, Germanyb - Departamento de Engenharia de Materiais, Escola de Engenharia de Lorena, University of Sao Paulo, Lorena-SP, BrazilFig.1 Optical microscopy (a) (c) (e) and SEM micrographs (b) (d) (f) of 13.5Cr ODS steel under various processing conditions (a) (b) HIP+HT; (c) (d) RD-ND section, HIP+TMP; (e) (f) TD-ND section, HIP+TMP, respectively. (a) (b) HIP+HT:equiaxed ferritic grains ; spherical second-phase precipitates(c) (d) RD-ND HIP+TMP:elongated grains ∥RD with a high aspect ratio(e) (f) TD-ND HIP+TMP:Less deformed grains, coarsen inclusions align preferable along GBFig.3 (a) Orientation distribution function (ODF) plots and (b) polefigures (PF) of 13.5Cr ODS steelThe developed texture has a sharp rotated-cube {100} <100>component. The γ-fiber, usually helpful for the improvement of ductility,is not present.Fig.4 Kernel average misorientation (KAM) map of 13.5Cr ODS steelFig.2 Orientation image map in RD-ND section and corresponding Highangle boundaries (above 15◦) are marked with black lines while lowangle boundaries (2–15◦) are marked with white lines. Elongated grains (∥RD)indicate that partialrecrystallization occurs duringTMP A bimodal grain sizedistribution is found with twomaxima at about 2 µm and 8 µmTMP does not influence the tensile strength markedly.Total elongation is more orientation- dependent compared with thetensile strength.Further efforts to improve toughness should be devoted tohomogenize the grain structure, decrease the fraction of largeinclusions and increase the intensity of γ-fiber texture component.Fig. 5 Tensile properties of 13.5Cr ODS and ferritic steels from RT to700 °C (a) tensile strength and (b) total elongation

Influence of thermomechanical treatment on the mechanical properties of 13.5Cr ODS steels

https://publikationen.bibliothek.kit.edu/220093445/3816410

Influence of thermomechanical treatment on the mechanical properties of 13.5Cr ODS steels

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