scholarly journals Positron and nanoindentation study of helium implanted high chromium ODS steels

2017 ◽  
Vol 68 (7) ◽  
pp. 62-65
Author(s):  
Jana Simeg Veternikova ◽  
Martin Fides ◽  
Jarmila Degmova ◽  
Stanislav Sojak ◽  
Martin Petriska ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Chromium Content ◽  
Nuclear Reactors ◽  
Oxide Dispersion Strengthened ◽  
Radiation Stability ◽  
Implantation Dose ◽  
Positron Annihilation Lifetime ◽  
Helium Ion ◽  
Ods Steels ◽  
Non Destructive

AbstractThree oxide dispersion strengthened (ODS) steels with different chromium content (MA 956, MA 957 and ODM 751) were studied as candidate materials for new nuclear reactors in term of their radiation stability. The radiation damage was experimentally simulated by helium ion implantation with energy of ions up to 500 keV. The study was focused on surface and sub-surface structural change due to the ion implantation observed by mostly non-destructive techniques: positron annihilation lifetime spectroscopy and nanoindentation. The applied techniques demonstrated the best radiation stability of the steel ODM 751. Blistering effect occurred due to high implantation dose (mostly in MA 956) was studied in details.

Advanced Fe-Cr Alloys Studied by Pulsed Low Energy Positron System Before and After Helium Ions Implantation

2009 ◽  
Author(s):  
Stanislav Sojak ◽  
Vladimi´r Krsˇjak ◽  
Werner Egger
Keyword(s):  
Research Reactor ◽  
Chromium Content ◽  
Depth Profiling ◽  
Positron Annihilation Spectroscopy ◽  
Implantation Dose ◽  
Low Energy ◽  
Microstructural Damage ◽  
Helium Ion ◽  
Before And After ◽  
Non Destructive

Positron annihilation spectroscopy (PAS) is a non-destructive technique which provides information about microstructural damage of structural materials. In this paper, the Pulsed Low Energy Positron System (PLEPS) at the research reactor FRM-II at TU Munich was used to study depth profiling of binary Fe-Cr alloys. Fe-Cr model alloys with different chromium content were investigated in the as-received state as well as after helium ion implantation (dose up to 6.24×1017 ions/cm−2). Measured results show changes in the size of defects after implantation and also in non-implanted specimens depending on the Cr content.

Vacancy Type Defects in Oxide Dispersion Strengthened Steels

2012 ◽  
Vol 733 ◽  
pp. 264-269
Author(s):  
Vladimir Slugeň ◽  
Jana Veterníková ◽  
Jarmila Degmová ◽  
S. Kilpeläinen ◽  
F. Tuomisto ◽  
...  
Keyword(s):  
Residual Stress ◽  
Chromium Content ◽  
Oxide Dispersion Strengthened ◽  
Defect Concentration ◽  
Barkhausen Noise ◽  
Oxide Dispersion ◽  
Magnetic Barkhausen Noise ◽  
Vacancy Defects ◽  
Positron Annihilation Lifetime ◽  
Ods Steels

This study was focused on commercial oxide-dispersion strengthened (ODS) steels - MA 956 (20%Cr), PM 2000 (19%Cr), ODM 751 (16%Cr) and MA 957 (14%Cr) developed for fuel cladding of GEN IV reactors. The ODS steels are described in order to comparison of their microstructure features. Vacancy defects were observed by Doppler Broadening Spectroscopy (DBS) and Positron Annihilation Lifetime Spectroscopy (PALS). Residual stress proportional to all kinds of defects was investigated by Magnetic Barkhausen Noise (MBN) measurement. The highest presence of open volume defects was found in MA 956 and the lowest defect concentration in MA 957, although this steel contains the largest defects (six-vacancies together with dislocations). Other investigated steels demonstrated probably three- or four-vacancy clusters. Further, results from positron technique indicated proportionality of chromium content to defect concentration. Magnetic Barkhausen noise results also showed that Hpeak value (describing grain size) increased with growth of chromium content. However residual stress was independent on chromium level.

Non Destructive Examination of Helium Implanted Fe-Cr Model Alloys

2009 ◽  
Author(s):  
V. Krsjak ◽  
S. Sojak ◽  
M. Petriska ◽  
J. Veternikova
Keyword(s):  
Chromium Content ◽  
Local Damage ◽  
Martensitic Steels ◽  
Positron Annihilation Lifetime ◽  
Vacancy Clusters ◽  
Cr Content ◽  
Helium Implantation ◽  
Displacement Per Atom ◽  
Induced Defects ◽  
Non Destructive

The helium implantation has been successfully used for the obtaining of radiation damage in different Fe-Cr ferritic/martensitic steels. Implanted doses within the range 6.24×1017 – 3.12×1018 cm−2 corresponding to local damage up to 90 DPA (Displacement per Atom) were acquired in a thin (<1 μm) region. For observing the dependence of vacancy-type defects on the load and the chromium content, positron annihilation lifetime spectroscopy (PALS) has been used. Experiments showed that chromium had a significant effect on the radiation treated microstructures of the materials. In particular, chromium influences the size and density of the implantation induced defects and specific Cr content should prevent the formation of vacancy clusters.

Radiation stability of nanoclusters in nano-structured oxide dispersion strengthened (ODS) steels

2013 ◽  
Vol 434 (1-3) ◽  
pp. 311-321 ◽  
Author(s):  
A. Certain ◽  
S. Kuchibhatla ◽  
V. Shutthanandan ◽  
D.T. Hoelzer ◽  
T.R. Allen
Keyword(s):  
Oxide Dispersion Strengthened ◽  
Radiation Stability ◽  
Oxide Dispersion ◽  
Ods Steels

scholarly journals Helium Ion Implantation Effects of 9Cr-ODS (Oxide Dispersion Strengthened) Steel

2013 ◽  
Vol 19 (S2) ◽  
pp. 1786-1787 ◽  
Author(s):  
C. Lu ◽  
Z. Lu ◽  
G. Yu ◽  
L. Wang
Keyword(s):  
Ion Implantation ◽  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Oxide Dispersion Strengthened Steel ◽  
Helium Ion

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

scholarly journals Microstructure and Mechanical Properties of 14Cr-ODS Steels with Zr Addition

2019 ◽  
Vol 38 (2019) ◽  
pp. 404-410 ◽  
Author(s):  
Weijuan Li ◽  
Haijian Xu ◽  
Xiaochun Sha ◽  
Jingsong Meng ◽  
Zhaodong Wang
Keyword(s):  
Mechanical Properties ◽  
Hot Isostatic Pressing ◽  
Oxide Dispersion Strengthened ◽  
Nominal Composition ◽  
Ods Steel ◽  
Zr Addition ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
Ods Steels ◽  
The Impact

AbstractIn this study, oxide dispersion strengthened (ODS) ferritic steels with nominal composition of Fe–14Cr–2W–0.35Y2O3 (14Cr non Zr-ODS) and Fe–14Cr–2W–0.3Zr–0.35Y2O3 (14Cr–Zr-ODS) were fabricated by mechanical alloying (MA) and hot isostatic pressing (HIP) technique to explore the impact of Zr addition on the microstructure and mechanical properties of 14Cr-ODS steels. Microstructure characterization revealed that Zr addition led to the formation of finer oxides, which was identified as Y4Zr3O12, with denser dispersion in the matrix. The ultimate tensile strength (UTS) of the non Zr-ODS steel is about 1201 MPa, but UTS of the Zr-ODS steel increases to1372 MPa, indicating the enhancement of mechanical properties by Zr addition.

Degradation in a Molybdenum-Gate MOS Structure Caused by N+ Ion Implantation for Work Function Control

2002 ◽  
Vol 716 ◽  
Author(s):  
Takaaki Amada ◽  
Nobuhide Maeda ◽  
Kentaro Shibahara
Keyword(s):  
Ion Implantation ◽  
Work Function ◽  
Nitrogen Concentration ◽  
Implantation Dose ◽  
Control Technique ◽  
High Dose ◽  
Implantation Energy ◽  
20 Nm ◽  
Large Work ◽  
Gate Work Function

AbstractAn Mo gate work function control technique which uses annealing or N+ ion implantation has been reported by Ranade et al. We have fabricated Mo-gate MOS diodes, based on their report, with 5-20 nm SiO2 and found that the gate leakage current was increased as the N+ implantation dose and implantation energy were increased. Although a work function shift was observed in the C-V characteristics, a hump caused by high-density interface states was found for high-dose specimens. Nevertheless, a work function shift larger than -1V was achieved. However, nitrogen concentration at the Si surface was about 1x1020 cm-3 for the specimen with a large work function shift.

Membrane folding by helium ion implantation for three-dimensional device fabrication

2007 ◽  
Vol 25 (6) ◽  
pp. 2184 ◽  
Author(s):  
William J. Arora ◽  
Sybren Sijbrandij ◽  
Lewis Stern ◽  
John Notte ◽  
Henry I. Smith ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Three Dimensional ◽  
Device Fabrication ◽  
Helium Ion

Ion-implantation Generated Nanovoids in Si and MgO Monitored by High Resolution Positron Beam Analysis

2000 ◽  
Vol 647 ◽  
Author(s):  
S.W.H. Eijt ◽  
C.V. Falub ◽  
A. van Veen ◽  
H. Schut ◽  
P.E. Mijnarends ◽  
...  
Keyword(s):  
High Resolution ◽  
Ion Implantation ◽  
Average Energy ◽  
Internal Surface ◽  
Positron Beam ◽  
Initial Energy ◽  
Thin Layers ◽  
Beam Analysis ◽  
Width Reduction ◽  
Non Destructive

AbstractThe formation of nanovoids in Si(100) and MgO(100) by 3He ion implantation has been studied. Contrary to Si in which the voids are generally almost spherical, in MgO nearly perfectly rectangular nanosize voids are created. Recently, the 2D-ACAR setup at the Delft Positron Research Center has been coupled to the intense reactor-based variable-energy positron beam POSH. This allows a new method of monitoring thin layers containing nanovoids or defects by depth-selective high-resolution positron beam analysis. The 2D-ACAR spectra of Si with a buried layer of nanocavities reveal the presence of two additional components, the first related to para-positronium (p-Ps) formation in the nanovoids, and a second one most likely related to unsaturated Si-bonds at the internal surface of the voids. The positronium is present in excited kinetic states with an average energy of 0.3 eV. Refilling of the cavities by means of low dose 3He implantation (1×1014 cm−2) followed by annealing reduces the formation of Ps and the width of the Ps peak in the ACAR spectrum. This width reduction is due to collisions of Ps with He atoms in the voids. In MgO, p-Ps formed with an initial energy of ~3 eV shows a final average energy of 1.6 eV at annihilation due to collisions with the cavity walls. Possibilities of this new, non-destructive method of monitoring the sizes of cavities and the evolution of nanovoid layers will be discussed.

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