Helium implanted RAFM steels studied by positron beam Doppler Broadening and Thermal Desorption Spectroscopy

16th International Conference on Positron Annihilation

Carvalho, I.^1,2 ; Schut, H.^2 ; Fedorov, A.^3 ; Luzginova, N.^3 ; Desgardin, P.^4 ; Sietsma, J.^5

Materials Innovation Institute (M2i), Mekelweg 2, 2628 CD, Delft, Netherlands^1

Delft University of Technology, Faculty of Applied Sciences, Mekelweg 15, 2629 JB, Delft, Netherlands^2

Nuclear Research and Consultancy Group (NRG), Westerduinweg 3, 1755 LE, Petten, Netherlands^3

CEMHTI-CNRS, 3A rue de la Férolerie, 45071 Orléans Cedex, France^4

Delft University of Technology, Faculty of Mechanical, Maritime and Materials Engineering, Mekelweg 2, 2628 CD, Delft, Netherlands^5

关键词: Atomic displacement;    Implantation-induced defects;    Implanted samples;    Irradiation conditions;    Reduced activation ferritic/martensitic steel;    Reference samples;    Thermal desorption spectroscopies (TDS);    Three temperature;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/443/1/012034/pdf
DOI  :  10.1088/1742-6596/443/1/012034

来源: IOP

【 摘 要 】

Reduced Activation Ferritic/Martensitic steels are being extensively studied because of their foreseen application in fusion and Generation IV fission reactors. To mimic neutron irradiation conditions, Eurofer97 samples were implanted with helium ions at energies of 500 keV and 2 MeV and doses of 5x1015-1016He /cm2, creating atomic displacements in the range 0.07-0.08 dpa. The implantation induced defects were characterized by positron beam Doppler Broadening (DB) and Thermal Desorption Spectroscopy (TDS). The DB data could be fitted with one or two layers of material, depending on the He implantation energy. The S and W values obtained for the implanted regions suggest the presence of not only vacancy clusters but also positron traps of the type present in a sub-surface region found on the reference sample. The traps found in the implanted layers are expected to be HenVmclusters. For the 2 MeV, 1016He/cm2implanted sample, three temperature regions can be observed in the TDS data. Peaks below 450 K can be ascribed to He released from vacancies in the neighbourhood of the surface, the phase transition is found at 1180 K and the peak at 1350 K is likely caused by the migration of bubbles.