Crack path and liquid metal embrittlement specificity of austenitic steels in mercury at room temperature

Thierry Auger (1) , Bassem Barkia (2) , Eva Héripré (2) , Vincent Michel (1) , Denis Mutel (2) , Ivan Guillot (3) , Zehoua Hamouche (1) , Liliana Medina-Almazàn (2)

1 PIMM - Laboratoire Procédés et Ingénierie en Mécanique et Matériaux
2 MSSMat - Laboratoire de mécanique des sols, structures et matériaux
3 ICMPE - Institut de Chimie et des Matériaux Paris-Est

A liquid metal embrittlement specificity of three austenitic steels with increasing nickel content (304 L, 316 L and 316L(N)) is studied in liquid mercury in the axisymmetric notched geometry. Only the low nickel alloys are susceptible to LME. The crack path of an austenitic steel fracture induced by liquid mercury has been elucidated at microstructural scale. Deformation induced martensite (γ(fcc) → α’(bcc)) of the low nickel steels induces numerous α’/α’ interfaces at small scale that are susceptible to be embrittled. Because the only steel that resists LME is the one that shows stability over α’ phase change due mostly to its higher nickel content, a point confirmed by X Ray fractography, it is inferred that the major factor contributing to the LME sensitivity at room temperature is the α’ phase formation in unstable austenitic steels during plastic strain. This provides a sound rationale on how to prevent mercury induced embrittlement with austenitic steels.

Mots clés: Condensed Matter Physics; General Materials Science; Mechanics of Materials; Metals and Alloys; Mechanical Engineering

Domaines: Sciences de l'ingénieur [physics]

Thierry Auger, Bassem Barkia, Eva Héripré, Vincent Michel, Denis Mutel, et al.. Crack path and liquid metal embrittlement specificity of austenitic steels in mercury at room temperature. Scripta Materialia, 2022, 215, pp.114733. ⟨10.1016/j.scriptamat.2022.114733⟩. ⟨hal-03708630⟩