Liquid metal embrittlement of a dual-phase Al0.7CoCrFeNi high-entropy alloy exposed to oxygen-saturated lead-bismuth eutectic

Xing Gong (1) , Congying Xiang (2) , Thierry Auger (3) , Jiajun Chen (1) , Xiaocong Liang (2) , Zhiyang Yu (2) , Michael P Short (4) , Min Song (5) , Yuan Yin (1)

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

This paper reports a new liquid metal embrittlement (LME) system in which a dual-phase Al0.7CoCrFeNi (equimolar fraction) high-entropy alloy (HEA) is embrittled by lead-bismuth eutectic (LBE) at 350 and 500°C. At 350°C, (Ni, Al)-rich BCC phase is embrittled, leading to intragrain cracking within this phase, while the predominant cracking mode changes to BCC/FCC phase boundary decohesion at 500°C. At both temperatures, cracks are rarely seen in the (Co, Cr, Fe)-rich FCC phase, indicating that this phase is immune to LME. Furthermore, the results suggest a transition from an adsorption-dominated LME mechanism at 350°C to a phase boundary wetting-dominated LME mechanism at 500°C.

Mots clés: General Materials Science; Condensed Matter Physics; LBE; Liquid metal embrittlement; High-entropy alloys; Cracking; Phase boundary wetting

Domaines: Mécanique des matériaux [physics.class-ph]

Xing Gong, Congying Xiang, Thierry Auger, Jiajun Chen, Xiaocong Liang, et al.. Liquid metal embrittlement of a dual-phase Al0.7CoCrFeNi high-entropy alloy exposed to oxygen-saturated lead-bismuth eutectic. Scripta Materialia, 2021, 194, pp.113652. ⟨10.1016/j.scriptamat.2020.113652⟩. ⟨hal-03268321⟩