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Communication Dans Un Congrès Année : 2022

Damage of an Alumina Austenitic Forming steel in presence of liquid lead and liquid lead bismuth eutectic: liquid metal embrittlement sensitivity

Résumé

One of the challenges in the development of the Lead cooled Fast Reactor (LFR) or accelerated driven systems (ADS) is to demonstrate the reliability of the structural materials, generally steels, in contact with the coolant, i.e. the liquid lead or liquid lead-bismuth eutectic (LBE). Without considering the possible irradiation damage, the life time of metallic materials in contact with liquid metal may be reduced due to damage caused by corrosion or/and modification of the mechanical behavior in presence of liquid metal. Especially, though tough and ductile metallic alloys are selected, they may become brittle when stressed in liquid metal exhibiting thus the so-called Liquid Metal Embrittlement (LME). It was shown that martensitic and ferritic steels with Body Center Cubic (BCC) structure suffers from LME in lead as in LBE, especially at temperature below 450°C. This LME sensitivity is explained by an adsorption-dominated LME mechanism. But, the studied austenitic steels such as 316L or 15-15Ti steels with a Face-Centered Cubic (FCC) structure presents no or insignificant LME sensitivity for temperature up to 450°C. That is why, the use of austenitic steels or FCC materials which seem less sensitive to LME, has been favoured in recent years. But because of the high content in Ni (and Mn), the corrosion resistance of theses steels in presence of liquid lead or LBE is less important than that of ferritic/martensitic steels and, is insufficient, especially for temperatures above 450°C. Therefore, to improve corrosion resistance while avoiding the LME, the characterization of alumina forming austenitic (AFA) steels is investigated at temperature up to 550 °C.The results presented in this communication concern the mechanical behaviour of one AFA steel (Fe12Cr15.8Ni2.7Al3.5Mn2.5Cu1Nb) in presence of lead and LBE at different temperatures between 350 °C and 550 °C. The influence of the presence of the liquid metal was investigated by performing tensile tests in air and in liquid LBE and liquid lead. After tests, cracking and fracture surfaces were analysed by SEM (scanning electron microscopy), EDX-SEM (energy dispersive X-ray) to characterize and understand the effect of the liquid metal on the damage. The studied AFA steel was also not sensitive to LME below 400 °C but suffers from LME above 450 °C. For the AFA steel, the liquid lead promoted at the highest temperatures an intergranular propagation of surface cracks which suggests a grain boundary wetting-dominated LME mechanism of this steel.
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Dates et versions

hal-03843591 , version 1 (08-11-2022)

Identifiants

  • HAL Id : hal-03843591 , version 1

Citer

Ingrid Proriol Serre, Jean-Bernard Vogt. Damage of an Alumina Austenitic Forming steel in presence of liquid lead and liquid lead bismuth eutectic: liquid metal embrittlement sensitivity. Eurocorr 2022, Aug 2022, Berlin, Germany. ⟨hal-03843591⟩
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