Liquid-Metal Embrittlement of Type 316L Stainless Steel by Gallium as Measured by Elastic-Plastic Fracture Mechanics

• Published in: Corrosion (Houston, Tex.) Tex.), 2004-03, Vol.60 (3), p.254-261
• Main Authors: Kolman, D.G., Chavarria, R.
• Format: Article
• Language: English
• Subjects: Adsorption; Applied sciences; Austenitic stainless steels; Compact tension; Corrosion; Corrosion mechanisms; Crack initiation; Crack propagation; Cracking (corrosion); Cracking (fracturing); Embrittlement; Exact sciences and technology; Fatigue; Fatigue failure; Fracture mechanics; Gallium; Growth rate; Liquid metal embrittlement; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Mechanics; Metal fatigue; Metals; Metals. Metallurgy; Plasticity; Stainless steel; Storage containers; Temperature
• ISSN: 0010-9312; 1938-159X
• DOI: 10.5006/1.3287729

ABSTRACTThere is a wide variety of plutonium-containing materials throughout the U.S. Department of Energy complex that require safe interim storage for 50 years. Some of these materials contain metallic Ga. Currently, it is planned to house these materials in nested austenitic stainless steel (SS) storage containers.1 The potential failure mechanisms for these containers have been discussed.2 Pu-compound storage temperatures are not sufficient to melt common Pu-Ga alloys or Pu-Ga-Fe alloys.3 However, elemental Ga melts at 29.8°C, well below expected storage container temperatures. Thus, a local accumulation of Ga-rich metal might form liquid Ga. It is unclear whether liquid Ga can embrittle austenitic stainless steels due to the paucity of data in the literature. Austenitic stainless steels have been shown to be liquid metal embrittled by metals other than Ga (e.g., Zn,4-5 Cu,6-7 Sn,8 Pb,9 and Te-Cs10-13). Also, liquid-metal embrittlement (LME) by Ga has been shown to be a problem for many materials,14 including Fe-3 Si,4,15-16 Fe,4,15,17 some steels,4,15,18 Al alloys,4,19-22 and Cu/brass.4,23-24 Therefore, it is possible that Ga metal may liquid metal embrittle austenitic stainless steels. Ga alloying of SS following liquid metal or suboxide gas (Ga2O) exposure has been shown to reduce dramatically the fracture toughness of austenitic SS compact tension (CT) specimens.25-26 However, it is unknown whether Type 316L (UNS S31603)(1) SS can be liquid metal embrittled by Ga. It is the objective of this study to assess the effect of liquid Ga on the fatigue and fracture resistance of Type 316L SS.