On the role of alloy composition and processing parameters in nanocluster formation and dispersion strengthening in nanostuctured ferritic alloys

Alinger, M.J.; Odette, G.R.; Hoelzer, David T.

doi:10.1016/j.actamat.2008.09.025

Cited by 374 publications

(240 citation statements)

References 38 publications

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“…No tantalum-containing carbides have been identified, possibly indicating segregation of this element at the oxide particles. Segregation of Ti to similar oxide particles in Ti-containing versions of high-Cr ODS materials (YWT alloys) has been observed [9]. The yttria dispersion presents the same morphology as observed in the SEM analysis, confirming average dimension and distribution.…”

Section: Microstructural Evolution As a Function Of Heat Treatmentsupporting

confidence: 62%

Effects of heat treatment conditions on the microstructure and impact properties of EUROFER 97 ODS steel

Martino¹,

Faulkner²,

Riddle³

et al. 2011

Phys. Scr.

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Probably the most important range of materials to consider for the blanket material in the tokamak design for fusion reactors such as ITER and DEMO is the high alloy Fe9Cr oxide dispersion strengthened (ODS) ferritic steels. These steels possess exceptional thermal conductivity and low thermal expansion while being strongly resistant to void swelling. Their main drawback is the high ductile-to-brittle transition temperature (DBTT), particularly in the ODS versions of the material. This paper describes attempts that are being made to reduce this DBTT in as yet unirradiated materials by a novel heat treatment procedure. The principle behind this approach is that low DBTT in the unirradiated materials will lead to relatively low DBTT even in He-containing material that has been irradiated with fusion blanket-type irradiations. New batches of high alloy Fe9Cr ODS (EUROFER) ferritic steel have been produced by a powder metallurgical route, and relatively homogeneous material has been produced by a hot isostatic pressing procedure. Mini-Charpy test specimens were made from materials that had been subjected to a matrix of heat treatments designed to show up variations in solution treatment (ST) temperature, cooling rate from the ST temperature and tempering treatment. The initial DBTT was in the range 150-200 • C. Extremely interesting results have been obtained. DBTT downward shifts of up to 200 • C have been observed by using a high 1300 • C ST temperature and a low cooling rate. The paper goes on to describe the microstructure of this material, and discusses the possible microstructural factors needed to produce these very high DBTT downward shifts. Low dissolved carbon and higher proportions of low-angle grain boundaries seem to provide the key to the understanding of the alloy behaviour.

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Section: Microstructural Evolution As a Function Of Heat Treatmentsupporting

confidence: 62%

Effects of heat treatment conditions on the microstructure and impact properties of EUROFER 97 ODS steel

Martino¹,

Faulkner²,

Riddle³

et al. 2011

Phys. Scr.

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“…4,5 The ODS alloys commercially produced at the end of the 20 th century and the beginning of the 21 st century are represented by MA 956 or MA 957 6 , PM 2000 or PM 2010 6 , ODM alloys 7 and 1DK or 1DS 8 with a ferritic matrix by ODS Eurofer steels with a tempered ferriticmartensitic matrix 9 and by austenitic Ni-ODS PM 1000 or Ni-ODS PM 3030. 10 ODS alloys are produced by high-energy milling of powder mixtures consisting of the alloying elements, master alloys and the oxide dispersion. The volume fraction of dispersed spherical oxides (usually Y 2 O 3 ) is typically below 1 % and the oxides are typically of a mean size of 5-30 nm.…”

Section: Introductionmentioning

confidence: 99%

Behaviour of new ODS alloys under single and multiple deformation

Mašek¹,

Khalaj²,

Nový³

et al. 2016

Mater. Tehnol.

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The application of innovative processing techniques to conventional raw materials can lead to new structural materials with specific mechanical and physical properties, which open up new possibilities of use in some areas of industry. The processing is enabled by powder metallurgy, which utilizes powders consisting of a metal matrix with dispersed stable particles achieved by mechanical alloying and their hot consolidation by rolling. New oxide dispersion strengthened (ODS) Fe-Al-based alloys are tested under different single and multiple thermomechanical treatments at different temperatures. The results show that new ODS alloys are significantly affected by the thermo-mechanical treatment, leading to microstructural changes. Their analysis is performed using different analytical methods such as optical microscopy, scanning electron microscopy and X-ray diffraction analysis. Keywords: ODS alloys, composite, steel, Fe-Al Uporaba inovativnih tehnik preoblikovanja na obi~ajnih materialih lahko privede do novih konstrukcijskih materialov s specifi~nimi mehanskimi in fizikalnimi lastnostmi, ki odpirajo nove mo`nosti uporabe v industriji. Metalurgija prahov omogo~a uporabo prahov s kovinsko osnovo z dispergiranimi stabilnimi delci, ki jih dobimo pri mehanskem legiranju in vro~i konsolidaciji z valjanjem. Nove zlitine Fe-Al, disperzijsko utrjene z oksidi (ODS), so bile preizku{ene pri razli~ni, eno-ali ve~stopenjski obdelavi pri razli~nih temperaturah. Rezultati ka`ejo, da ima termomehanska obdelava novih ODS zlitin mo~an vpliv, ki se vidi v spremembah mikrostrukture. Analiza je bila izvedena s pomo~jo razli~nih analitskih metod, kot so: svetlobna mikroskopija, vrsti~na elektronska mikroskopija in rentgenska difrakcijska analiza.

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“…For comparison, Fe-14Cr-3W-0.2Ti (14WT) and Fe-14Cr-3W-0.2Ti-0.25Y 2 O 3 (14YWT), typical of ODS steels for nuclear applications, [10] were also produced using pre-alloyed 14WT (< 150 lm, Aubert and Duval) and Y 2 O 3 (20 to 40 nm, PI-KEM Ltd.) powders and conventional MA-based processing. The raw materials were MA'ed using a Fritsch P5 Pulverisette ball mill (60 hours, 250 rpm, 10:1 ball to powder weight ratio), followed by hot isostatic pressing into bulk at 1423 K and 150 MPa for 4 hours.…”

Section: Methodsmentioning

confidence: 99%

“…[1][2][3][4][5] The widely practiced processing route for these ODS steels is essentially a two-step powder metallurgy process, consisting of mechanical alloying (MA) of 10-to 90-lm-diameter pre-alloyed Fe-based alloy powder together with a normally nano-sized (20 to 50 nm) Y 2 O 3 powder until fine-scale mixing/alloying is achieved, followed by consolidation of the powder into a bulk form typically by hot isostatic pressing (HIP) or related technique. [5][6][7][8][9][10] This MA approach is now well optimized and convenient for laboratory-based studies, providing good quality material sufficient for detailed microscopy, irradiation, and mechanical property assessment. However, in technological terms, disadvantages of the MA route include prolonged processing time, small batch size, tendency for contamination associated with the high specific area of the powder, and the high inherent cost of the pre-alloyed feedstock powders, which combine to restrict wider commercial implementation of the MA-based route.…”

Section: Ferritic Oxide Dispersion-strengthened (Ods)mentioning

confidence: 99%

Development of a Novel Melt Spinning-Based Processing Route for Oxide Dispersion-Strengthened Steels

Hong

Morrison

Zhang

et al. 2017

Metall Mater Trans A

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Melt spinning of an Fe-5Y and Fe-1Y-1Ti (wt pct) alloy produced a relatively uniform spatial distribution of Y and Ti in solid solution and ribbons with consistent yield (>60 pct by weight), fast processing time (< 10 seconds), good scalability (up to > 100 g feedstock material), and repeatability. Heat treatment in the presence of Fe 2 O 3 as an oxygen source (Rhines pack method) at 973 K validated the potential of forming < 20 nm Y-rich oxides in the Fe-5Y ribbons. Pulverized Fe-1Y-1Y ribbons were consolidated to bulk using the field-assisted sintering technique (FAST) incorporating nano-sized Fe 3 O 4 powder as the oxygen source. After FAST at 1273 K, 50 MPa, and 30 minutes, a comparatively high number density of sub-micron Y and/or Ti-rich oxides were developed. Further formation of fine-scale oxides took place during post-FAST annealing, resulting in an approximate 20 pct increase in hardness at temperatures below 573 K, but with a reduced hardening effect above 673 K due to a small fraction of persistent porosity and mechanically weak prior ribbon boundaries that were decorated with Ti-rich oxides.

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On the role of alloy composition and processing parameters in nanocluster formation and dispersion strengthening in nanostuctured ferritic alloys

Cited by 374 publications

References 38 publications

Effects of heat treatment conditions on the microstructure and impact properties of EUROFER 97 ODS steel

Effects of heat treatment conditions on the microstructure and impact properties of EUROFER 97 ODS steel

Behaviour of new ODS alloys under single and multiple deformation

Development of a Novel Melt Spinning-Based Processing Route for Oxide Dispersion-Strengthened Steels

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