Characterization of Specimens Exposed in a Li Loop

Conference · Tue Jan 01 04:00:00 EST 2013

OSTI ID:1130824

Unocic, Kinga A ^[1]; Lance, Michael J ^[1]; Pint, Bruce A ^[1]

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1. ORNL

A monometallic V-4Cr-4Ti thermal convection loop was run for 2,350 h with a peak temperature of 700 C and Li flow rate of 2-3 cm/s. Specimens of V-4Cr-4Ti exposed in the hot and cold leg were tensile tested in vacuum at 500 C showing an increase in the 0.2% yield and ultimate tensile strengths and a decrease in the serration amplitude with decreasing exposure temperature in the loop. However, only minor changes in ductility were measured. With the higher temperature exposures, there was a decrease in Vickers hardness measured but little change in the grain size. Characterization of the microstructure after exposure at 627 C in the loop showed an increase in the density of Ti- and N-rich grain boundary and matrix precipitates near the specimen surface after exposure corresponding to an increase in the hardness in the near-surface region. Two-layer V/Y2O3 coatings on V-4Cr-4Ti substrates also were exposed in the loop and initial room temperature characterization has been conducted.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1130824
• Country of Publication: United States
• Language: English