Microstructure and mechanical properties of ultrafine-grained Fe-14Cr and ODS Fe-14Cr model alloys.
TL;DR: In this article, the reduced activation ferritic Fe-14-wt%Cr and Fe- 14-t%Cr-0.3%Y 2 O 3 alloys were produced by mechanical alloying and hot isostatic pressing followed by forging and heat treating.
About: This article is published in Journal of Nuclear Materials.The article was published on 2011-10-01 and is currently open access. It has received 36 citations till now. The article focuses on the topics: Hot isostatic pressing & Heat treating.
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TL;DR: The microstructure, mechanical, tribological, and corrosion properties of Fe–Cr–Al–Y-based oxide-precipitation-hardened (OPH) alloy at room temperature are presented and the ultimate tensile strength increased up to 300% more compared to the initial state.
Abstract: The microstructure, mechanical, tribological, and corrosion properties of Fe–Cr–Al–Y-based oxide-precipitation-hardened (OPH) alloy at room temperature are presented. Two OPH alloys with a composition of 0.72Fe–0.15Cr–0.06Al–0.03Mo–0.01Ta–0.02Y2O3 and 0.03Y2O3 (wt.%) were prepared by mechanical alloying with different milling times. After consolidation by hot rolling, the alloys presented a very fine microstructure with a grain size of approximately 180 nm. Such a structure is relatively brittle, and its mechanical properties are enhanced by heat treatment. Annealing was performed at three temperatures (1000 °C, 1100 °C, and 1200 °C), with a holding time from 1 to 20 h. Tensile testing, wear testing, and corrosion testing were performed to evaluate the effect of heat treatment on the behavior and microstructural properties. The grain size increased almost 10 times by heat treatment, which influenced the mechanical properties. The ultimate tensile strength increased up to 300% more compared to the initial state. On the other hand, heat treatment has a negative effect on corrosion and wear resistance.
6 citations
Cites background from "Microstructure and mechanical prope..."
...Oxide-dispersion-strengthened (ODS) or oxide-precipitation-hardened (OPH) alloys are extinguished by their significant high strength and advanced creep properties, as well as reasonable resistance to swelling, hardening, and embrittlement [1,2]....
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TL;DR: In this paper, the effect of strengthened elements (Y2O3 and TiO2) on the microstructure has been investigated in Fe-14Cr-1 W based ferritic steels.
5 citations
TL;DR: In this paper, the authors used the Finite Element Method to simulate the co-extrusion of a powder Metallurgy (PM) grade in a soft steel can, and determined the PM steel grade behavior law by hot torsion tests, taking into account temperature and strain-rate sensitivity.
Abstract: Oxides Dispersed strengthened (ODS) stainless steels are foreseen for fuel cladding tubes in the coming generation of fission nuclear reactors. In spite of a ferritic matrix those steels present a convenient creep behavior thanks to very fine oxides dispersion. Those grades are currently obtained by Powder Metallurgy (PM). After mechanical alloying with the oxide, the powder is commonly consolidated by Hot Isostatic Pressing (HIP) or Hot Extrusion (HE). The control of microstructure after extrusion is a key issue for this grade regarding service conditions. On CEA facilities, new ferritic ODS stainless steels are produced by HE. In order to explain the microstructure observed at various places on an interrupted extrusion samples the thermo-mechanical history applied to the material must be determined. In this paper we use the Finite Element Method to simulate the co-extrusion of a PM grade in a soft steel can. The PM steel grade behavior law is determined on a fully dense material by hot torsion tests, taking into account temperature and strain-rate sensitivity. Thus strain and thermal history are computed for material points lying on various flow lines during extrusion.
5 citations
TL;DR: In this article, a FeAl-O ODS alloy prepared via mechanical alloying was subjected to three different heat treatments and showed a fine-grained microstructure with fine dispersion of aluminum oxide particles (60% up to 20 nm).
Abstract: Fe–Al–O ODS alloy prepared via mechanical alloying was subjected to three different heat treatments. Material basic state exhibited a fine-grained (300–500 nm) microstructure with fine dispersion of aluminum oxide particles (60% up to 20 nm). Heat treatment at 1100 °C for 3 h resulted in local grain and particles coarsening. Prolongation of the heat treatment to 24 h resulted in further grain (50 % up to 5 μm) and particle (25 % with size 25–40 nm) coarsening. Annealing at 1200 °C for 24 h led to a bimodal microstructure (35 % of grains with size 100–250 μm and 45 % of particles with size 30–60 nm) and substantial oxide particle coarsening. Microstructural changes resulted in tensile strength decrease and ductility increase. Tensile tests at 800 °C revealed a 90% decrease of tensile strength while ductility increased 4–6 times when compared to the room temperature tests. The hardening ratio was below 10 % for all the alloys and both test temperatures.
4 citations
TL;DR: In this article, the state of Y2O3, as a major additive element in Fe-based ODS alloys, during mechanical alloying (MA) processes by thermodynamic approaches and experimental verification was investigated.
Abstract: In this study, we investigated the state of Y2O3, as a major additive element in Fe-based ODS alloys, during mechanical alloying (MA) processes by thermodynamic approaches and experimental verification. For this purpose, we introduced Ti2O3 that formed different reaction products depending on the state of Y2O3 into the Fe-based ODS alloys. In addition, the reaction products of Ti2O3, Y, and Y2O3 powders were predicted approximately based on their formation enthalpy. The experimental results relating to the formation of Y-based complex oxides revealed that YTiO3 and Y2Ti2O7 were formed when Ti2O3 reacted with Y; in contrast, only Y2Ti2O7 was detected during the reaction between Ti2O3 and Y2O3. In the alloy of Fe–Cr–Y2O3 with Ti2O3, YTiO3 (formed by the reaction of Ti2O3 with Y) was detected after the MA and heat treatment processes were complete, even though Y2O3 was present in the system. Using these results, it was proved that Y2O3 decomposed into monoatomic Y and O during the MA process.
3 citations
References
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TL;DR: WinPLOTR is a graphic program for the analysis of powder diffraction patterns that has been developed for a Windows 9x/2k/NT environment and can be used as a Graphic User Interface for programs defined by the user.
Abstract: WinPLOTR is a graphic program for the analysis of powder diffraction patterns. It has been developed for a Windows 9x/2k/NT environment. It takes advantage of this graphical environment to offer a powerful and user-friendly powder diffraction tool. The program is able to display and analyse many different kinds of diffraction patterns as well as calculated and observed profiles coming from the Windows/DOS version of the program FullProf. It can also be used as a Graphic User Interface (GUI) for programs defined by the user.
1,638 citations
TL;DR: The use of the Voigt function for the analysis of the integral breadths of broadened X-ray diffraction line profiles forms the basis of a rapid and powerful single-line method of crystallite size and strain determination which is easy to apply.
Abstract: The use of the Voigt function for the analysis of the integral breadths of broadened X-ray diffraction line profiles forms the basis of a rapid and powerful single-line method of crystallite-size and strain determination which is easy to apply. To avoid graphical methods or interpolation from tables, empirical formulae of high accuracy are used and an estimation of errors is presented, including the influence of line-profile asymmetry. The method is applied to four practical cases of size-strain broadening: (i) cold-worked nickel, (ii) a nitrided steel, (iii) an electrodeposited nickel layer and (iv) a liquid-quenched AlSi alloy.
1,085 citations
TL;DR: In this article, the authors reviewed the JNC activities on ODS steel development as "nano-composite materials" and concluded that the ODS-technology development achieved in the field of fast reactors should be effectively spun off to the fusion reactor first wall and blanket structural materials to allow for safe and economical reactor design.
673 citations
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01 Jul 2001
523 citations
"Microstructure and mechanical prope..." refers background in this paper
...Fe–Cr binary alloys are nowadays the most promising base to fabricate reduced-activation ferritic/martensitic (RAFM) and ferritic (RAF) steels for structural applications in future fusion reactors as well as in generation IV fission reactors [1–3]....
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TL;DR: In this article, the differences and similarities of different ODS steels are explained in terms of the microstructures of the steels, and observations are explained using the properties of the ODS micro-structures.
478 citations