Liquid–metal-induced fracture mode of martensitic T91 steels

• Published in: Journal of nuclear materials Vol. 426; no. 1-3; pp. 71 - 77
• Main Authors: Martin, M.L., Auger, T., Johnson, D.D., Robertson, I.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2012; Elsevier
• Subjects: Applied sciences; Beams (radiation); Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Engineering Sciences; Exact sciences and technology; Ferritic stainless steels; Fission nuclear power plants; Fracture mechanics; Fuels; Grain boundaries; Installations for energy generation and conversion: thermal and electrical energy; Martensitic stainless steels; Mechanics; Mechanics of materials; Metallurgy; Microstructure; Networks; Nuclear fuels; Physics; Steels; Liquid metal; Martensitic steel; Embrittlement; Fracture; Fracture surface; Microstructure; Carbides; Crack; Grain boundary; Crack propagation; Nuclear reactor
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2012.03.040

The liquid–metal-induced fracture mode of T91 martensitic steel was investigated by using transmission electron microscopy techniques to characterize the microstructure and crack network in specimens obtained from focused-ion beam machining at and immediately below the fracture surface. Contrary to previous claims of quasi-cleavage fracture, the dominant fracture mode is intergranular cracking at martensite laths and prior austenite grain boundaries. These fracture mode results clarify an outstanding issue in liquid–metal embrittlement of steels that generally occur in a heavily-deformed microstructure. Several cracks were arrested at intergranular carbides, suggesting a metallurgical strategy for impeding liquid–metal-induced crack propagation.