Microstructure, Texture and Mechanical Properties of the 14YWT Nanostructured Ferritic Alloy NFA-1

Pal, Soupitak; Alam, Ershadul; Odette, G.R.; Maloy, Stuart A.; Hoelzer, David T.; Lewandowski, John J.

doi:10.1007/978-3-319-51097-2_4

Cited by 9 publications

(11 citation statements)

References 4 publications

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“…Development of strong γ fiber has been reported to be good for the deep drawing ability of high chrome-ferritic steels [48]. It also supports the finding that the hydrostatically extruded final tube in Process II can be produced without cracking as reported by Pal et al [24].…”

Section: Discussionsupporting

confidence: 81%

“…Additional deformation processing steps to improve properties and/or fabricate shapes are also severely impacted by these characteristics of the HE condition. For example, HE cross-rolled plates develop microcracks [23] and deformation processed tubes experience radial through-wall cracks [24]. Extensive research in Japan and France have identified semi-optimized processing paths for tubing that differ in detail, but in both cases involve a series of cold-pilgering steps to reduce the wall thickness, with intermediate and final heat treatment softening schedules [5,25,26].…”

Section: Introductionmentioning

confidence: 99%

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Effect of tube processing methods on the texture and grain boundary characteristics of 14YWT nanostructured ferritic alloys

Aydoğan

Pal

Anderoglu

et al. 2016

Materials Science and Engineering: A

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Texture and microstructure of tubes and plates fabricated from a nanostructured ferritic alloy (14YWT), produced either by spray forming followed by hydrostatic extrusion (Process I) or hot extrusion and cross-rolling a plate followed by hydrostatic tube extrusion (Process II) have been characterized in terms of their effects on texture and grain boundary character. Hydrostatic extrusion results in a combination of plane strain and shear deformations which generate low intensity α-and γ-fiber components of {001}<110> and {111}<110> together with a weak ζfiber component of {011}<211> and {011}<011>. In contrast, multi-step plane strain deformation by hot extrusion and cross-rolling of the plate leads to a strong texture component of {001}<110> together with a weaker {111}<112> component. Although the total strains are similar, shear dominated deformation leads to much lower texture indexes compared to plane strain deformations. Further, the texture intensity decreases after hydrostatic extrusion of the alloy plate formed by plane strain deformation, due to a lower number of activated slip systems during shear dominated deformation. Notably, hot extruded and cross-rolled plane strain plate deformation to ~50% engineering strain creates only a modest population of low angle grain boundaries (LABs), compared to the much larger population observed following the combination of plane strain and shear deformation of ~44% engineering strain resulting from subsequent hydrostatic extrusion.

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Section: Discussionsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Effect of tube processing methods on the texture and grain boundary characteristics of 14YWT nanostructured ferritic alloys

Aydoğan

Pal

Anderoglu

et al. 2016

Materials Science and Engineering: A

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“…Nanostructured ferritic alloys (NFAs) are a revolutionary class of Fe-Cr-based oxide dispersion strengthened (ODS) steels with many outstanding mechanical, thermal, and chemical properties for nuclear applications [1][2][3][4][5][6][7][8][9][10] . NFAs have high temperature strength and stability up to 900 °C [11 , 12] and unmatched radiation resistance, especially with respect to managing helium generated by nuclear transmutation reactions [1 , 13-18] .…”

Section: Introductionmentioning

confidence: 99%

Characterization of polyhedral nano-oxides and helium bubbles in an annealed nanostructured ferritic alloy

Stan

Ciston

et al. 2020

Acta Materialia

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“…Further, these grains are not preferentially associated with microcracks. As reported by Pal et al [32,35], the responsible deformation mechanism for microcracking can be summarized as follows. High temperature cross-rolling deformation results in a strong {100}<011> texture that also produces sessile a<001> dislocations on {100} Fig.…”

Section: Microstructural Characterizationmentioning

confidence: 93%

“…Thus, a key objective of this research is to understand the causes and consequences of preexisting microcracks to the fracture toughness of NFA-1 as a function of orientation and temperature, in specimens containing sharp primary pre-cracks in various pertinent loading orientations. Note, a very brief, in-progress summary of some results of this research were reported in a conference proceedings volume that covered several other topics, but with only a summary discussion [32].…”

Section: Introductionmentioning

confidence: 99%

On delamination toughening of a 14YWT nanostructured ferritic alloy

et al. 2017

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The FCRD NFA-1 is a high strength, irradiation tolerant nanostructured ferritic alloy (NFA) produced by ball milling argon atomized Fe-14Cr-3W-0.35Ti-0.25Y (wt.%) and FeO powders, followed by hot extrusion at 850ºC, and subsequent annealing and crossrolling at 1000ºC. The microstructure of the resulting ≈ 10 mm thick NFA-1 plate is dominated by ultrafine sub-micron pancake shaped grains, and a large population of microcracks lying on planes parallel to the plate faces. Pre-cracked fracture toughness tests in four different orientations (L-T, T-L, L-S and T-S) show stable crack growth by ductile tearing, with peak load KJc from ≈ 88 to 154 MPa√m at ambient temperature. Stable crack tearing persists down to ≈-175°C and is accompanied by extensive delamination due to the propagation of the microcracks. Depending on the specimen orientation, this unusual toughening mechanism is either due to reduction of crack tip stresses in thin ligaments formed by the delaminations (L-T and T-L), or 90° deflection of cracks initially running normal to the delaminations (L-S and T-S), thereby 2 suppressing cleavage in both cases. Understanding the fracture processes in NFA-1 is also important to its irradiation tolerance in nuclear service as well as its fabricability in making defect-free components such as thin-walled tubing.

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Microstructure, Texture and Mechanical Properties of the 14YWT Nanostructured Ferritic Alloy NFA-1

Cited by 9 publications

References 4 publications

Effect of tube processing methods on the texture and grain boundary characteristics of 14YWT nanostructured ferritic alloys

Effect of tube processing methods on the texture and grain boundary characteristics of 14YWT nanostructured ferritic alloys

Characterization of polyhedral nano-oxides and helium bubbles in an annealed nanostructured ferritic alloy

On delamination toughening of a 14YWT nanostructured ferritic alloy

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