Intergranular precipitation-enhanced wetting and phase transformation in an Al0.4CoCrFeNi high-entropy alloy exposed to lead-bismuth eutectic

Xing Gong (1) , Thierry Auger (2) , Wenjian Zhu (1) , Huasheng Lei (3) , Congying Xiang (3) , Zhiyang Yu (3) , Michael Short (4) , Pei Wang (1) , Yuan Yin (1)

1 Shenzhen University [Shenzhen]
2 PIMM - Laboratoire Procédés et Ingénierie en Mécanique et Matériaux
3 Fuzhou University [Fuzhou]
4 MIT - Massachusetts Institute of Technology

After exposure to oxygen-poor (10^-13–10^-14 wt%) liquid lead-bismuth eutectic (LBE) at 500°C for 500 h, LBE penetrates more than one order of magnitude deeper in an FCC Al0.4CoCrFeNi high-entropy alloy (HEA) deco-rated with a network of BCC (Ni, Al)-rich intergranular (IG) precipitates than in a single-phase, FCC Al0.3CoCrFeNi HEA without the IG precipitate network. This deterioration of corrosion resistance is attributed to the energetic nature of the BCC/FCC interphase boundaries (IBs) and resultant IB wetting. The LBE ingress film selectively leaches nickel located at those low-indexed crystalline planes, resulting in phase transformation from FCC to BCC structure.

Mots clés: General Materials Science

Domaines: Sciences de l'ingénieur [physics]

Xing Gong, Thierry Auger, Wenjian Zhu, Huasheng Lei, Congying Xiang, et al.. Intergranular precipitation-enhanced wetting and phase transformation in an Al0.4CoCrFeNi high-entropy alloy exposed to lead-bismuth eutectic. Corrosion Science, 2022, 196, ⟨10.1016/j.corsci.2021.110038⟩. ⟨hal-03736337⟩