Biaxial thermal creep of two heats of V4Cr4Ti at 700 and 800 °C in a liquid lithium environment

• Published in: Journal of nuclear materials 2007-08, Vol.367 (1), p.788-793
• Main Authors: Li, Meimei, Nagasaka, T., Hoelzer, D.T., Grossbeck, M.L., Zinkle, S.J., Muroga, T., Fukumoto, K., Matsui, H., Narui, M.
• Format: Article
• Language: English
• Subjects: ALLOYS; Applied sciences; Controled nuclear fusion plants; CREEP; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; LITHIUM; MATERIALS SCIENCE; NITROGEN; Nuclear fuels; OXYGEN; PRODUCTION; REMOVAL; RUPTURES; VANADIUM ALLOYS
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2007.03.081

This paper presents biaxial thermal creep results for the vanadium alloy V4Cr4Ti in liquid lithium using US Heat 832665 and two batches of tubing made from NIFS-Heat-2. The tests were performed at 700 and 800 °C over a stress range of 30–120 MPa using pressurized tube specimens. Lithium environments changed C, N and O concentrations in V4Cr4Ti. Oxygen removal from the alloy to lithium was small when there was a significant pickup of nitrogen during exposures. The creep response of V4Cr4Ti was characterized by an inverted primary creep followed by a secondary creep or an accelerating creep up to creep rupture. A normal primary creep was also observed in US Heat 832665 when tested at 700 °C and 120 MPa. Improved creep rupture properties were observed in the JP-NIFS-Heat-2 specimens compared to the US-NIFS-Heat-2 specimens. Creep response of V4Cr4Ti is apparently dependent on the heat, tubing production, and stress and temperature conditions.