Correlative TEM and APT of Helium Bubbles in Ion-Irradiated RAFM Steel

The behavior of helium in reduced-activation ferritic/martensitic steels was investigated systematically with positron annihilation Doppler broadening measurement and thermal desorption spectroscopy. Specimens were irradiated with helium ions with different energies to various fluences at different temperatures. A threshold fluence was observed above which the rate of formation and growth of helium bubbles dramatically increased. Irradiation at higher temperature could suppress the formation and growth of HenVm clusters with low binding energies and enhance that of helium bubbles and HenVm clusters with high binding energies. Different changes of S parameters were observed in various depth after the irradiation temperature was increased from 523 K to 723 K. Irradiation of 18 keV-He+ enhanced the growth of HenVm clusters and helium bubbles compared with 100 keV-He+ irradiation. A possible mechanism is discussed.

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In-Situ TEM Annealing Observation of Helium Bubble Evolution in Pre-Irradiated FeCoNiCrTi0.2 Alloys

Materials ◽

10.3390/ma14133727 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3727

Author(s):

Huanhuan He ◽

Zhiwei Lin ◽

Shengming Jiang ◽

Xiaotian Hu ◽

Jian Zhang ◽

...

Keyword(s):

Vacuum Arc ◽

In Situ Tem ◽

Face Centered Cubic ◽

Helium Bubble ◽

High Entropy ◽

Helium Bubbles ◽

Transmission Electron ◽

Bubble Evolution ◽

Face Centered

The FeCoNiCrTi0.2 high-entropy alloys fabricated by vacuum arc melting method, and the annealed pristine material, are face centered cubic structures with coherent γ’ precipitation. Samples were irradiated with 50 keV He+ ions to a fluence of 2 × 1016 ions/cm2 at 723 K, and an in situ annealing experiment was carried out to monitor the evolution of helium bubbles during heating to 823 and 923 K. The pristine structure of FeCoNiCrTi0.2 samples and the evolution of helium bubbles during in situ annealing were both characterized by transmission electron microscopy. The annealing temperature and annealing time affect the process of helium bubbles evolution and formation. Meanwhile, the grain boundaries act as sinks to accumulate helium bubbles. However, the precipitation phase seems have few effects on the helium bubble evolution, which may be due to the coherent interface and same structure of γ’ precipitation and matrix.

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Effect of helium bubbles on irradiation hardening of additive manufacturing 316L stainless steel under high temperature He ions irradiation

Journal of Nuclear Materials ◽

10.1016/j.jnucmat.2021.152948 ◽

2021 ◽

pp. 152948

Author(s):

Chonglong Fu ◽

Jianjian Li ◽

Juju Bai ◽

Ying Li ◽

Qian Chen ◽

...

Keyword(s):

Stainless Steel ◽

High Temperature ◽

Additive Manufacturing ◽

316L Stainless Steel ◽

Irradiation Hardening ◽

Helium Bubbles

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Experimental Development at a Pilot Plant Scale of a Reduced Activation Ferritic/Martensitic RAFM Steel, Asturfer®

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.73.36 ◽

2010 ◽

Vol 73 ◽

pp. 36-40 ◽

Cited By ~ 3

Author(s):

Ana Morán ◽

Rubén Coto ◽

Javier Belzunce ◽

Jose Manuel Artímez

Keyword(s):

Stainless Steels ◽

Pilot Plant ◽

Austenitic Stainless Steels ◽

Martensitic Steels ◽

Font Size ◽

Experimental Development ◽

Pilot Plant Scale ◽

Fusion Material ◽

Rafm Steel ◽

The Eu

Ferritic/Martensitic steels, with chromium contents ranging between 9 and 12%, were introduced into fusion material programs due to their better creep resistance and excellent thermal and nuclear properties compared to austenitic stainless steels. Reduced activation ferritic/martensitic (RAFM) steels are considered promising candidates for the test blanket modules of the future International Thermonuclear Experimental Reactor (ITER), being EUROFER steel is the EU reference material. It is a 9 % Cr RAFM steel which exhibits a tempered martensitic microstructure and presently allows operation up to 550 ⁰C. This paper shows the work carried out to develop at a pilot plant scale a Reduced Activation Ferritic/Martensitic (RAFM) steel, Asturfer ®, with chemical composition and mechanical properties very close to EUROFER steel.

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