SANS study on the stability of oxide nanoparticles in long-term thermally aged 9Cr-ODS steel

2021 ◽  
Author(s):  
Peng-Lin Gao ◽  
Jian Gong ◽  
Qiang Tian ◽  
Gung-Ai Sun ◽  
Hai-Yang Yan ◽  
...  
Keyword(s):  
Oxide Dispersion Strengthened ◽  
Oxide Nanoparticles ◽  
Electron Backscattered Diffraction ◽  
Excellent Thermal Stability ◽  
Ods Steel ◽  
Transmission Electron ◽  
Hardness Tests ◽  
The Stability ◽  
Thermal Stability Of

Abstract A 9Cr-oxide dispersion strengthened (ODS) steel was thermally aged at 873 K for up to 5000 hours. The size distribution and chemical composition of the dispersed oxide nanoparticles were analyzed by small angle neutron scattering (SANS) method under magnetic field. Combined with transmission electron microscopy (TEM), Vickers micro-hardness tests and electron backscattered diffraction (EBSD) measurements, all the results showed that the thermal treatment had little or no effect on the size distributions and volume fractions of the oxide nanoparticles in the ferromagnetic matrix, which suggested excellent thermal stability of the 9Cr-ODS steel.

scholarly journals Inhibition Effect of Ti on the Formation of Martensite Lath in 14Cr Oxide Dispersion Strengthened Steel

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 802 ◽  
Author(s):  
Qian Zhao ◽  
Zongqing Ma ◽  
Liming Yu ◽  
Huijun Li ◽  
Zumin Wang ◽  
...  
Keyword(s):  
Oxide Dispersion Strengthened ◽  
Friction Material ◽  
Martensite Lath ◽  
Oxide Dispersion ◽  
Secondary Phases ◽  
Ods Steel ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Cr Depletion ◽  
The Stability

Three model powders defined as MP powders (milled pre-alloyed powders), mixed powders (MX, 50 wt.% MP powders + 50 wt.% Oxide-Dispersion Strengthened powders) and Oxide Dispersion Strengthened (ODS) powders (alloyed pre-alloyed powders with the addition of Ti and Y2O3) are obtained under identical ball milling parameters. These powders are then consolidated under same sintering condition by spark plasma sintering (SPS) in order to investigate the formation mechanism of martensite lath in the MP steel and the effect of Ti on the stability of ferrite. The results indicate that the addition of Y2O3 and Ti powders can act as friction material during the mechanical alloying process, thus promoting the refinement effect. The formation of martensite lath in the MP steel is attributed to the local Cr depletion resulted from the large amounts of M23C6 precipitation. Ti possesses a strong affinity to C and long range diffusion ability, which efficiently prevents the martensite lath formation and local Cr depletion. Present study supports the conclusion that the lack of martensite in the MX and ODS steel is due to the addition of Ti. Secondary phases in these steels are identified and analyzed as well.

Ta2O5-Incorporated WO3 Nanocomposite Film for Improved Electrochromic Performance in an Acidic Condition

2006 ◽  
Vol 6 (11) ◽  
pp. 3572-3576 ◽  
Author(s):  
Hee-Sang Shim ◽  
Hyo-Jin Ahn ◽  
Youn-Su Kim ◽  
Yung-Eun Sung ◽  
Won Bae Kim
Keyword(s):  
Surface Roughness ◽  
Photoelectron Spectroscopy ◽  
Potential Cycling ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Continuous Potential ◽  
Chemical States ◽  
The Stability

We report electrochromic and electrochemical properties of a WO3-Ta2O5 nanocomposite electrode that was fabricated from co-sputtering. Transmission electron microscopy (TEM)images of the WO3-Ta2O5 nanocomposite electrode revealed that morphology of the WO3 film was changed by incorporation of Ta2O5 nanoparticles, and their chemical states were confirmed to be W6+ and Ta5+ oxides from X-ray photoelectron spectroscopy (XPS). The introduction of Ta2O5 to the WO3 film played a role in alleviating surface roughness increase during continuous potential cycling; whereas the surface roughness of the WO3 film was increased from ca. 3.0 nm to ca. 13.4 nm after 400 cycles, the roughness increase on the WO3-Ta2O5 was significantly reduced to 4.2 nm after 400 cycles, as investigated by atomic force microscopy (AFM). This improvement of the stability by adding Ta2O5 may be responsible for the enhanced electrochemical and optical properties over long-term cycling with the WO3-Ta2O5 nanocomposite electrode.

scholarly journals Microstructure characterization of ODS-RAFM steels

2008 ◽  
Vol 1125 ◽  
Author(s):  
R. Mateus ◽  
P.A. Carvalho ◽  
D. Nunes ◽  
L.C. Alves ◽  
N. Franco ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Proton Beam ◽  
Nuclear Microprobe ◽  
Elemental Distribution ◽  
Electron Backscattered Diffraction ◽  
Ods Steel ◽  
Transmission Electron ◽  
Eurofer 97

ABSTRACTResults of the microstructural characterization of four different RAFM ODS Eurofer 97 batches are presented and discussed. Analyses and observations were performed by nuclear microprobe and scanning and transmission electron microscopy. X-ray elemental distribution maps obtained with proton beam scans showed homogeneous composition within the proton beam spatial resolution and, in particular, pointed to a uniform distribution of ODS (yttria) nanoparticles in the Eurofer 97 matrix. This was confirmed by transmission electron microscopy. Scanning electron microscopy coupled with energy dispersive spectroscopy made evident the presence of chromium carbide precipitation. Precipitates occurred preferentially along grain boundaries (GB) in three of the batches and presented a discrete distribution in the other, as a result of different thermo-mechanical routes. Additional electron backscattered diffraction experiments revealed the crystalline textures in the ferritic polycrystalline structure of the ODS steel samples.

scholarly journals On Long-Term Stability of Metallic Glasses

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1076 ◽  
Author(s):  
Louzguine-Luzgin ◽  
Jiang
Keyword(s):  
Metallic Glasses ◽  
Surface Oxidation ◽  
Initial Structure ◽  
Ambient Conditions ◽  
Scanning Calorimetry ◽  
Long Term Stability ◽  
Transmission Electron ◽  
Different Types ◽  
Thermal Stability Of

Thermal stability of different types of metallic glasses and partially crystalline alloys stored for at least 15 years at ambient conditions was tested in the present work by differential scanning calorimetry in comparison with that of the original alloys tested in the as-cast state in the earlier works. The structure of the naturally aged alloys was also studied by X-ray diffractometry. The structure of a couple of selected alloys was also tested by transmission electron microscopy. Most of the alloys retained their initial structure and showed only a moderate decrease in the crystallization temperature. Only those alloys which showed visible surface oxidation (Cu-Zr-system based) were partly transformed into a crystalline state forming micron-scale Cu particles in air at ambient conditions.

scholarly journals Quantitative analysis of stability of 9%Cr steel microstructure after long-term ageing

2017 ◽  
Vol 62 (1) ◽  
pp. 263-271 ◽  
Author(s):  
G. Golański ◽  
J. Jasak ◽  
A. Zieliński ◽  
C. Kolan ◽  
M. Urzynicok ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Favorable Effect ◽  
Scanning Microscope ◽  
Steel Microstructure ◽  
Transmission Electron ◽  
The Matrix ◽  
The Mean ◽  
Analysis Of Stability ◽  
The Stability

Abstract The paper presents the results of research on the microstructure of martensitic X10CrMoVNb9-1 (P91) and X13CrMoCo- VNbNB9-2-1 (PB2) steel subject to long-term ageing at the temperature of 620°C and holding times up to 30 000 hours. The microstructural tests of the examined steel types were performed using a scanning microscope Joel JSM - 6610LV and a transmission electron microscope TITAN 80 - 300. The stability of the microstructure of the investigated steels was analyzed using a quantitative analysis of an image, including measurements of the following: the density of dislocations inside martensite/subgrain laths, the width of martensite laths, and the mean diameter of precipitates. It has been concluded that during long-term ageing, the microaddition of boron in PB2 steel significantly influenced the slowing of the process of degradation of the martensitic steel microstructure, as a result of slowing the process of coagulation of M23C6 carbides and Laves phase. It had a favorable effect on the stabilization of lath microstructure as a result of retardation of the processes of recovery and polygonization of the matrix.

The Thermal Stability of a Single-Grain Mg-Zn-Y Icosahedral Quasicrystal

2000 ◽  
Vol 643 ◽  
Author(s):  
Z.P. Luo ◽  
Y.L. Tang ◽  
D.J. Miller ◽  
M.J. Kramer ◽  
I.R. Fisher ◽  
...  
Keyword(s):  
Golden Ratio ◽  
Lattice Parameter ◽  
Icosahedral Quasicrystal ◽  
Face Centered Cubic ◽  
Single Grain ◽  
Face Centered ◽  
The Stability ◽  
Mg Content ◽  
Thermal Stability Of

AbstractThe stability of the Mg-Zn-Y icosahedral quasicrystal (IQC) has been studied by long-term annealing of a single grain IQC in quartz tubes. Decomposition of the IQC was observed after annealing at high temperatures (T≥773 K) sealed in Ar. During the decomposition process, the quasilattice parameter aR was found to decrease, associated with a decrease in Mg content of the IQC phase as confirmed by quantitative x-ray energy dispersive spectroscopy analyses. In addition, a new cubic approximant has been found in the annealed samples. This cubic approximant has a face-centered cubic (fcc) structure with lattice parameter of a = 1.276 nm, which is about (1/τ) times smaller than that of the fcc W'-(MgZnY) with a = 2.05 nm reported previously (where τ is the golden ratio).

Thermal Stability of Ti-6Al-4V Alloy with Carbon Content

2015 ◽  
Vol 226 ◽  
pp. 23-28
Author(s):  
Agnieszka Szkliniarz
Keyword(s):  
Carbon Content ◽  
Operating Temperature ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Hardness Test ◽  
Two Phase ◽  
Microstructure Stability ◽  
The Stability ◽  
Thermal Stability Of

In the paper, the effect of long-term annealing (to 500 h) on the microstructure and hardness of two-phase titanium alloy which represent group of α+β (Ti-6Al-4V) with 0.7 wt. % carbon content was present. The stability of microstructure after long-term annealing was conducted to alloys in hardening state (after solution treatment and aging). Annealing was carried out at a temperature above the operating temperature of commercial titanium alloys without carbon content. The analysis of changes in the microstructure at research range of annealing time indicates its stability, which was confirmed by hardness test of investigated alloys. For comparison to Ti-6Al-4V-0.7C alloy, the microstructure stability research at 420oC was conducted for classical alloy contain no carbon. This alloy was previously subject solution and aging treatment under the same conditions as tested alloy.

Structure and Properties of PM Nano-Crystalline Al-Cr based Alloys

2007 ◽  
Vol 567-568 ◽  
pp. 197-200
Author(s):  
Dalibor Vojtěch ◽  
Alena Michalcová ◽  
Jan Verner ◽  
Jan Šerák ◽  
František Šimančík ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Elevated Temperature ◽  
Tensile Tests ◽  
Paper Properties ◽  
Excellent Thermal Stability ◽  
Nano Crystalline ◽  
Rapidly Solidified ◽  
Thermal Stability Of ◽  
Powder Fraction

In the presented paper, properties of Al-Cr-Fe-Ti alloy produced by powder metallurgy (PM) are described. Rapidly solidified powder alloy was prepared by the pressure nitrogen melt atomization. The granulometric powder fraction of less than 45 μm was then hot-extruded. Microstructure of the as-extruded material comprised recrystallized α-Al grains and spheroids of intermetallic phases. Tensile strength of the investigated material was similar to that of a conventional casting Al-Si alloy commonly used in elevated temperature applications. Excellent thermal stability of the PM Al-Cr based material, which much exceeded the elevated temperature casting alloy, was proved by room temperature tensile tests after long-term annealing at elevated temperature. Reasons for the observed thermal stability of the investigated PM alloy are discussed.

scholarly journals A Comparison of “Bottom-Up” and “Top-Down” Approaches to the Synthesis of Pt/C Electrocatalysts

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 947
Author(s):  
Alexandra Kuriganova ◽  
Nikita Faddeev ◽  
Mikhail Gorshenkov ◽  
Dmitri Kuznetsov ◽  
Igor Leontyev ◽  
...  
Keyword(s):  
Alternating Current ◽  
X Ray Diffraction ◽  
Platinum Nanoparticle ◽  
X Ray ◽  
Transmission Electron ◽  
Electrochemically Active ◽  
Electrochemical Dispersion ◽  
The Stability ◽  
Nanoparticle Sizes

Three 40 wt % Pt/C electrocatalysts prepared using two different approaches—the polyol process and electrochemical dispersion of platinum under pulse alternating current—and a commercial Pt/C catalyst (Johnson Matthey prod.) were examined via X-ray diffraction (XRD) and transmission electron microscopy (TEM). The stability characteristics of the Pt/C catalysts were studied via long-term cycling, revealing that, for all cycling modes, the best stability was achieved for the Pt/C catalyst with the largest platinum nanoparticle sizes, which was synthesized via electrochemical dispersion of platinum under pulse alternating current. Our results show that the mass and specific electrocatalytic activities of Pt/C catalysts toward ethanol electrooxidation are determined by the value of the electrochemically active Pt surface area in the catalysts.

scholarly journals Application of Adaptive Evolution to Improve the Stability of Bacteriophages during Storage

Viruses ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 423
Author(s):  
Kelvin K. Kering ◽  
Xiaoxu Zhang ◽  
Raphael Nyaruaba ◽  
Junping Yu ◽  
Hongping Wei
Keyword(s):  
Heat Treatment ◽  
Adaptive Evolution ◽  
Antibacterial Agents ◽  
Critical Factor ◽  
Wild Type ◽  
The Stability ◽  
Tubular Proteins ◽  
Thermal Stability Of ◽  
General Method

Phage stability is important for the successful application of bacteriophages as alternative antibacterial agents. Considering that temperature is a critical factor in phage stability, this study aimed to explore the possibility of improving long-term phage stability through adaptive evolution to elevated temperature. Evolution of three wild-type ancestral phages (Myoviridae phage Wc4 and Podoviridae phages CX5 and P-PSG-11) was induced by subjecting the phages to heat treatment at 60 °C for five cycles. The adapted phages showed better stability than the wild-type ancestral phages when subjected to heat treatment at 60 °C for 1 h and after 60 days of storage at 37 °C. However, the adapted phages could not withstand thermal treatment at 70 °C for 1 h. The infectivity and the lytic properties of the phages were not changed by the evolution process. Whole-genome sequencing revealed that single substitutions in the tail tubular proteins were the only changes observed in the genomes of the adapted phages. This study demonstrates that adaptive evolution could be used as a general method for enhancing the thermal stability of phages without affecting their lytic activity. Sequencing results showed that bacteriophages may exist as a population with minor heterogeneous mutants, which might be important to understand the ecology of phages in different environments.

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