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Effect of the Initial Microstructure on Defect Evolution in Neutron Irradiated Fe-Cr-C Alloys

100%

Brodziansky T., Slugeň V., Sojak S., Petriska M., Konstantinović M.

Acta Physica Polonica A

2017

vol. 132

issue 5

1590-1592

The irradiation-induced evolution of vacancy type defects in various iron-chromium model alloys and high chromium ferritic/martensitic steels have been studied using coincidence Doppler broadening spectroscopy. Specimens were neutron irradiated to 0.11 dpa at two different temperatures, 290°C and 450°C. It has been found that the microstructure (ferrite vs. ferrite/martensite), more precisely distribution of dissolved carbon within the matrix, is one of the key factor that affect response of the materials to neutron irradiation. Presence of dissolved carbon within the matrix leads to formation of stable and immobile carbon-vacancy complexes which act as traps for irradiation induced vacancies and therefore, leading to increased formation of vacancy clusters. Impact of carbon-vacancy complexes on defects evolution during neutron irradiation is relevant only for certain irradiation temperatures.

Study of Oxide-Dispersion-Strengthened Ferritic Steels after Ion Implantation

86%

Simeg Veternikova J., Korhonen E., Skarba M., Degmova J., Sabelova V., Sojak S., Slugen V.

Acta Physica Polonica A

2014

vol. 125

issue 3

741-743

This paper is focused on four different commercial oxide-dispersion-strengthened ferritic steels (MA 956, ODM 751, MA 957 and ODS Eurofer) with different chromium content and the change of their microstructure after helium ion implantation. The samples were implanted with kinetic energy of ions up to 500 keV and the implantation depth was up to 1.2 μm. The implantation was performed at Institute of Nuclear and Physical Engineering, Slovak University of Technology in Bratislava. The samples were observed prior and after the implantation by positron Doppler broadening spectroscopy with slow positron beam (energy up to 36 keV) which is one of the most suitable techniques due to its sensitivity to surface and subsurface layers up to 1.6 μm. The results showed visible change of defect presence in all samples and defect depth profiles are in a good accordance with SRIM software calculations displaying the Bragg peak. According to measured data, ODS Eurofer (9% Cr) seems to be the most radiation resistant from the group of all investigated steels and MA 956 (20% Cr) as the most radiation affected steel.

German and Russian Irradiated Reactor Pressure Vessel Steels from PAS Point of View

73%

Slugeň V., Hein H., Sojak S., Pecko S., Šimeg Veterníková J., Petriska M., Sabelová V., Bartošová I., Stacho M.

Acta Physica Polonica A

2014

vol. 125

issue 3

726-728

This paper presents a comparison of commercially used German and Russian reactor pressure vessel steels from the positron annihilation spectroscopy point of view, having in mind knowledge obtained also from other techniques from the last decades. The second generation of Russian reactor pressure vessel steels seems to be fully comparable with German steels and their quality allows prolongation of NPP operating lifetime over projected 40 years. The embrittlement of CrMoV steels is very low due to the dynamic recovery of radiation-induced defects at reactor operating temperatures. Positron annihilation spectroscopy techniques can be effectively applied for evaluation of microstructural changes caused by extreme external loads by proton implantation, with aim to simulate irradiation and for the evaluation of the effectiveness of post-irradiation thermal treatments. We used our actual and previous results, collected during last 20 years from measurements of different reactor pressure vessel steels in "as received", irradiated and post-irradiation annealed state and compare them with the aim to contribute to general knowledge based on experimental positron annihilation spectroscopy data.

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3 Acta Physica Polonica A

1 2017

2 2014

3 Sojak S.

2 Petriska M.

2 Slugeň V.

1 Bartošová I.

1 Brodziansky T.

1 Degmova J.

1 Hein H.

1 Konstantinović M.

1 Korhonen E.

1 Pecko S.

1 Sabelova V.

1 Sabelová V.

1 Simeg Veternikova J.

1 Skarba M.

1 Slugen V.

1 Stacho M.

1 Šimeg Veterníková J.

Search results

Effect of the Initial Microstructure on Defect Evolution in Neutron Irradiated Fe-Cr-C Alloys

Study of Oxide-Dispersion-Strengthened Ferritic Steels after Ion Implantation

German and Russian Irradiated Reactor Pressure Vessel Steels from PAS Point of View