Speaker
Mr
David McGuire
(National High Magnetic Field Laboratory)
Description
Due to the potential spatial temperature variations during heat treatment of the large central solenoid (CS) coils, it is necessary to study the strand’s heat treatment sensitivity by characterizing the strands heat treated with slightly different temperature profiles. We present critical current (Ic) and residual resistivity ratio (RRR) results of ITER Nb3Sn strands made by two manufacturers for CS coils that were heat treated using varying temperatures and durations for the last stage of the heat treatment. Our results show that Ic is not very sensitive to the heat treatment for the range of temperature and time used, however, RRR did decrease with increasing heat treatment time and temperature. We will discuss the mechanisms responsible for the heat treatment sensitivity of Ic and RRR for the two strands. In particular, an expression of RRR as a function of heat treatment temperature and time is presented.
*This work is funded by US-ITER under subcontract number 4000110684.*
Author
Mr
David McGuire
(National High Magnetic Field Laboratory)
Co-authors
Dr
Jun Lu
(National High Magnetic Field Laboratory)
Kevin Chan
(Oak Ridge National Laboratory)
Mr
Nicolai Martovetsky
(Oak Ridge National Laboratory)
