المؤلفون: Yasuhiro Kamada, Daiki Umeyama, Takeshi Murakami, Kazuyuki Shimizu, Hideo Watanabe

المصدر: Metals, Vol 14, Iss 5, p 568 (2024)

مصطلحات موضوعية: iron–chromium alloy, epitaxial film, ion irradiation, helium cavity, magnetization curve, Mining engineering. Metallurgy, TN1-997

الوصف: This study reports on the magnetic hardening phenomenon of heavily helium ion-irradiated iron–chromium alloys. The alloys are important structural materials in next-generation nuclear reactors. In some cases, problems may arise when the magnetic properties of the materials change due to neutron irradiation. Therefore, it is necessary to understand the effects of irradiation on magnetism. Helium irradiation was conducted as a simulated irradiation, and the effect of cavity formation on magnetic properties was thoroughly investigated. High-quality single-crystal Fe-x%Cr (x = 0, 10, 20) films, with a thickness of 180–200 nm, were fabricated through ultra-high vacuum evaporation. Subsequently, irradiation of 19 dpa with 30 keV He+ ions was conducted at room temperature. X-ray diffraction measurements and electron microscopy observations confirmed significant lattice expansion and the formation of high-density cavities after irradiation. The magnetization curve of pure iron remained unchanged, while magnetic hardening was noticed in iron–chromium alloys. This phenomenon is believed to be due to the combined effect of cavity formation and changes in the atomic arrangement of chromium.

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/2075-4701/14/5/568Test; https://doaj.org/toc/2075-4701Test

الوصول الحر: https://doaj.org/article/cead40f5e07340b38f58bdc7dad10b61Test

المؤلفون: Alicja Łukaszczyk, Jacek Banaś, Marcin Pisarek, Antoine Seyeux, Philippe Marcus, Jolanta Światowska

المصدر: Electrochem, Vol 2, Iss 4, Pp 546-562 (2021)

مصطلحات موضوعية: iron-chromium alloy, low Cr-alloy steel, oxide layer, XPS, ToF-SIMS, passivation, Industrial electrochemistry, TP250-261

الوصف: The electrochemical behavior of low alloyed Fe-Cr steels with 3 and 5% wt. of Cr in neutral Na2SO4 electrolyte combined with a detailed chemical and morphological characterization of these alloys performed by Auger electron spectroscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry and scanning electron microscopy are presented here. The corrosion of low alloyed Fe-Cr steels proceeds in the prepassive range, with the formation of corrosion surface films having a duplex structure with outer iron oxide/hydroxide layer and inner Cr oxide-rich layer. The thickness, composition, and the morphology of the surface films vary as a function of chromium content in the alloy as well as conditions of electrochemical tests (temperature). Even a low chromium content shows a beneficial effect on the corrosion performances of the Fe-Cr steels. The chromium as a more active component than iron of ferrite increases the anodic activity of this phase, which results in a rapid saturation of the surface with the anodic reaction products forming a fine crystalline-like and compact layer of corrosion products. In this way, the chromium acts as a modifier of formation/crystallization of the iron-rich surface film (mainly magnetite) in the prepassive range.

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/2673-3293/2/4/35Test; https://doaj.org/toc/2673-3293Test

الوصول الحر: https://doaj.org/article/bfb7c7ff347e4b899c76470508f428afTest

المؤلفون: Kuopanportti, Pekko, Ropo, Matti, Holmberg, Daniel, Levamaki, Henrik, Kokko, Kalevi, Granroth, Sari, Kuronen, Antti

المساهمون: Department of Physics

مصطلحات موضوعية: Iron-chromium alloy, Molecular dynamics, Tersoff potential, EMBEDDED-ATOM METHOD, ORDER, ALLOYS, MINIMIZATION, ENERGIES, STATE, 114 Physical sciences

الوصف: To enable accurate molecular dynamics simulations of iron-chromium alloys with surfaces, we develop, based on density-functional-theory (DFT) calculations, a new interatomic Fe-Cr potential in the Tersoff formalism. Contrary to previous potential models, which have been designed for bulk Fe-Cr, we extend our potential fitting database to include not only conventional bulk properties but also surface-segregation energies of Cr in bcc Fe. In terms of reproducing our DFT results for the bulk properties, the new potential is found to be superior to the previously developed Tersoff potential and competitive with the concentration-dependent and two-band embedded-atom-method potentials. For Cr segregation toward the (100) surface of an Fe-Cr alloy, only the new potential agrees with our DFT calculations in predicting preferential segregation of Cr to the topmost surface layer, instead of the second layer preferred by the other potentials. We expect this rectification to foster future research, e.g., on the mechanisms of corrosion resistance of stainless steels at the atomic level. ; Peer reviewed

وصف الملف: application/pdf

العلاقة: This work was supported by the Academy of Finland (Grants No. 308632 and No. 308633) . The computational resources granted by the CSC - IT Center for Science, Finland, and by the Finnish Grid and Cloud Infrastructure project (FGCI; urn:nbn:fi:research-infras-2016072533) are gratefully acknowledged, as are the facilities provided by the Turku University Centre for Materials and Surfaces (MatSurf) .; Kuopanportti , P , Ropo , M , Holmberg , D , Levamaki , H , Kokko , K , Granroth , S & Kuronen , A 2022 , ' Interatomic Fe-Cr potential for modeling kinetics on Fe surfaces ' , Computational Materials Science , vol. 203 , 110840 . https://doi.org/10.1016/j.commatsci.2021.110840Test; ORCID: /0000-0003-0795-8003/work/106337446; e54ce3fb-7536-4226-abaf-cd60b4b0065b; http://hdl.handle.net/10138/338530Test; 000734348800002

الإتاحة: http://hdl.handle.net/10138/338530Test

المؤلفون: Yanhua Zhao, Wei Meng, Peifu Wang, Chuanbin Du, Xiaowei Wang

المصدر: Materials, Vol 15, Iss 3234, p 3234 (2022)

مصطلحات موضوعية: laser additive manufacturing, iron-chromium alloy, rare earth oxide, microstructure, wear performance, Technology, Electrical engineering. Electronics. Nuclear engineering, TK1-9971, Engineering (General). Civil engineering (General), TA1-2040, Microscopy, QH201-278.5, Descriptive and experimental mechanics, QC120-168.85

الوصف: Additive Manufacturing (AM) has become increasingly common, and its use in various industries is increasing. However, the microstructure, friction and wear performance of metals made by AM, such as the inexpensive and relatively good-performing iron-chromium alloys, require further investigation. Generally, adding rare earth elements can effectively improve the performance of AM alloys, such as tensile strength, wear resistance, corrosion resistance, creep resistance, etc. This work aims to study the variation of microstructure, friction and wear properties of laser additive manufacturing processed iron-chromium alloys after adding different mass fractions of La 2 O 3 . The observations obtained by scanning electron microscopy showed that, with the addition of La 2 O 3 , the microstructure of AM alloy becomes more uniform and the grains are significantly refined. It is found by friction test that the running-in period is significantly shortened after the addition of La 2 O 3 . The coefficient of friction is reduced to a minimum of 0.68. Compared with AM alloys without La 2 O 3 , the wear rate of AM alloys with La 2 O 3 is significantly reduced, with a maximum reduction of 38%. Using an optical microscope to observe the surface morphology of the wear scar, it is found that, after adding rare earth oxide, the wear mechanisms changed from adhesive wear and abrasive wear to abrasive wear, with the spalling of hard particles at the same time.

العلاقة: https://www.mdpi.com/1996-1944/15/9/3234Test; https://doaj.org/toc/1996-1944Test; https://doaj.org/article/3188112dc4d14b649ec5aebba1c8ec6eTest

الإتاحة: https://doi.org/10.3390/ma15093234Test
https://doaj.org/article/3188112dc4d14b649ec5aebba1c8ec6eTest

المساهمون: Caro, Alfredo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)]

المصدر: Acta Materialia; 89; C; Other Information: CMIME partners with Los Alamos National Laboratory (lead); Carnegie Mellon University; University of Illinois, Urbana Champaign; Massachusetts Institute of Technology; University of Nebraska

وصف الملف: Medium: ED; Size: p. 116-122

الوصول الحر: http://www.osti.gov/scitech/servlets/purl/1369954Test

المؤلفون: Bergner, Frank, Hernández-Mayoral, Mercedes, Heintze, Cornelia, Konstantinović, Milan J., Malerba, Lorenzo, Pareige, Cristelle

مصطلحات موضوعية: iron–chromium alloy, neutron irradiation, hardening, tensile test, dislocation loop, TEM

الوصف: Several open issues remain concerning the quantitative understanding of irradiation hardening in high-Cr steels. One of these issues is addressed here by correlating yield points that are observed in stress–strain curves with dislocation decoration observed by TEM for neutron-irradiated Fe–Cr alloys. It is found that both higher neutron exposure and higher Cr content promote irradiation-induced loops to arrange preferentially along dislocation lines. Consequently, the activation of dislocation sources requires unlocking from the decorating loops, thus resulting in a yield drop. This process is considered within the source hardening model as opposed to the dispersed barrier hardening model, the latter aimed to describe dislocation slip through a random array of obstacles. Microstructure-informed estimates of the unlocking stress are compared with measured values of the upper yield stress. As functions of neutron exposure, a cross-over from the dominance of dispersed-barrier hardening accompanied by smooth elastic–plastic transitions to the dominance of source hardening accompanied by yield drops is observed for Fe–9%Cr and Fe–12%Cr.

العلاقة: info:eu-repo/grantAgreement/EC/H2020/755039/; https://zenodo.org/communities/h2020-m4fTest; https://zenodo.org/record/3613462Test; https://doi.org/10.3390/met10010147Test; oai:zenodo.org:3613462

الإتاحة: https://doi.org/10.3390/met10010147Test
https://zenodo.org/record/3613462Test

المؤلفون: Frank Bergner, Mercedes Hernández-Mayoral, Cornelia Heintze, Milan J. Konstantinović, Lorenzo Malerba, Cristelle Pareige

المصدر: Metals; Volume 10; Issue 1; Pages: 147

مصطلحات موضوعية: iron-chromium alloy, neutron irradiation, hardening, tensile test, dislocation loop, TEM

الوصف: Several open issues remain concerning the quantitative understanding of irradiation hardening in high-Cr steels. One of these issues is addressed here by correlating yield points that are observed in stress-strain curves with dislocation decoration observed by TEM for neutron-irradiated Fe-Cr alloys. It is found that both higher neutron exposure and higher Cr content promote irradiation-induced loops to arrange preferentially along dislocation lines. Consequently, the activation of dislocation sources requires unlocking from the decorating loops, thus resulting in a yield drop. This process is considered within the source hardening model as opposed to the dispersed barrier hardening model, the latter aimed to describe dislocation slip through a random array of obstacles. Microstructure-informed estimates of the unlocking stress are compared with measured values of the upper yield stress. As functions of neutron exposure, a cross-over from the dominance of dispersed-barrier hardening accompanied by smooth elastic-plastic transitions to the dominance of source hardening accompanied by yield drops is observed for Fe-9% Cr and Fe-12% Cr.

وصف الملف: application/pdf

العلاقة: Metal Failure Analysis; https://dx.doi.org/10.3390/met10010147Test

الإتاحة: https://doi.org/10.3390/met10010147Test

المؤلفون: Ken-ichi SAITOH, Masanori TAKUMA, Tomohiro SATO, Xiang Li, Yoshimasa TAKAHASHI, 佐藤 知広, 宅間 正則, 李 響, 高橋 可昌, 齋藤 賢一

المصدر: The Proceedings of Mechanical Engineering Congress, Japan. 2021, :J031-30

المؤلفون: Pillis, Marina Fuser, Correa, Olandir Vercino, Ramanathan, Lalgudi Venkataraman

المصدر: Materials Research. June 2016 19(3)

مصطلحات موضوعية: Iron-chromium alloy, Yttrium dioxide, Coating, Oxidation behavior, High temperature

الوصف: Long term isothermal and cyclic oxidation behavior of yttrium dioxide (Y2O3) coated Fe-20Cr alloy was studied. Oxidation tests were carried out in air for periods of up to 200 hours at 1000°C and the oxidation behavior of the alloy was evaluated gravimetrically. The Y2O3 coating reduced markedly the mass gain of the alloy. Energy dispersive spectroscopic analysis of scale sections on oxidized Y2O3 coated specimens revealed a Cr rich layer close to the metal/oxide interface and the presence of Y and Cr near the oxide/air interface, indicating diffusion of Cr through the Y2O3 layer. Further evidence of this diffusion was seen as change in colour of the Y2O3 coating from white to green after prolonged oxidation. X-ray diffraction analysis of the scale revealed perovskite-type YCrO3.This study attributes the increased oxidation resistance of the Y2O3 coated Fe-20Cr alloy to increased oxygen ion diffusion through the Cr2O3 scale due to YCrO3 formation and grain boundary segregated Y ion blocking alloy cation diffusion.

وصف الملف: text/html

الوصول الحر: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392016000300611Test

المؤلفون: Marina Fuser Pillis, Olandir Vercino Correa, Lalgudi Venkataraman Ramanathan

المصدر: Materials Research, Vol 19, Iss 3, Pp 611-617 (2016)

مصطلحات موضوعية: Iron-chromium alloy, Yttrium dioxide, Coating, Oxidation behavior, High temperature, Materials of engineering and construction. Mechanics of materials, TA401-492

الوصف: Long term isothermal and cyclic oxidation behavior of yttrium dioxide (Y2O3) coated Fe-20Cr alloy was studied. Oxidation tests were carried out in air for periods of up to 200 hours at 1000°C and the oxidation behavior of the alloy was evaluated gravimetrically. The Y2O3 coating reduced markedly the mass gain of the alloy. Energy dispersive spectroscopic analysis of scale sections on oxidized Y2O3 coated specimens revealed a Cr rich layer close to the metal/oxide interface and the presence of Y and Cr near the oxide/air interface, indicating diffusion of Cr through the Y2O3 layer. Further evidence of this diffusion was seen as change in colour of the Y2O3 coating from white to green after prolonged oxidation. X-ray diffraction analysis of the scale revealed perovskite-type YCrO3.This study attributes the increased oxidation resistance of the Y2O3 coated Fe-20Cr alloy to increased oxygen ion diffusion through the Cr2O3 scale due to YCrO3 formation and grain boundary segregated Y ion blocking alloy cation diffusion.

وصف الملف: electronic resource

العلاقة: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392016000300611&tlng=enTest; http://www.scielo.br/pdf/mr/v19n3/1516-1439-mr-1980-5373-MR-2015-0393.pdfTest; https://doaj.org/toc/1516-1439Test

الوصول الحر: https://doaj.org/article/a5968d68fcdc4209adba6fd3578ed2dcTest