On the fatigue crack growth behavior of Ti–10V–2Fe–3Al in gaseous hydrogen. (16th October 2020)

• Record Type: Journal Article
• Authors: Harris, Zachary D.; Ronevich, Joseph A.; Stavila, Vitalie; Somerday, Brian P.
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 51(2020)
• Page Start: 27929
• Page End: 27940
• Publication Date: 2020-10-16
• Subjects: Hydrogen embrittlement -- Fatigue -- Ti-10-2-3 -- Hydride formation -- Hydrogen compatibility; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2020.07.046
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The fatigue crack growth behavior of Ti–10V–2Fe–3Al in gaseous hydrogen (H2 ) was assessed through comparative experiments conducted in laboratory air and 8.3 MPa H2 . The measured fatigue crack growth rate (da/dN) versus applied stress intensity factor range (ΔK) relationships and observed fracture morphologies for laboratory air and H2 were comparable up to ΔK ≈ 6.9 MPa√m, when tested at a load ratio of 0.1 and frequency of 10 Hz. At higher ΔK values, significant crack deflection and subsequent catastrophic failure occurred in the specimen tested in H2 . This degradation was not observed in a specimen pre-exposed to 8.3 MPa H2 for 96 h and then immediately tested in laboratory air. X-ray diffraction of the failed H2 -tested specimen revealed that the material remnants were predominantly composed of TiH2, suggesting that hydride formation was the catalyst for catastrophic failure in H2 . The mechanistic implications of these results and their impact on current material compatibility assessments for Ti alloys in hydrogen service are then discussed. Highlights: Ti–10V–2Fe–3Al cyclically loaded in gaseous hydrogen exhibited catastrophic failure. Pre-exposure to hydrogen did not affect subsequent fatigue behavior. Hydride formation was observed for concurrent cyclic loading and hydrogen exposure. A critical ΔK and/or da/dN is likely required for hydride formation to occur. Results highlight need to refine hydrogen compatibility guidance in design codes.