Abstract
Low-temperature mechanical behaviors have been investigated for the constituent materials of superconducting radio frequency cavities. Test materials consist of small grain Nb, single crystal Nb, large grain Nb (bicrystal), Ti45Nb-Nb weld joint (e-beam welded), and Ti-316L bimetal joint (explosion welded). The strength of all test metals displayed strong temperature dependence and the Ti-316L bimetal showed the highest strength and lowest ductility among the test materials. The fracture toughness of the small grain Nb metals decreased with decreasing test temperature and reached the lower shelf values (30-40 MPa √m) at or above 173 K. The Ti45Nb base and Ti45Nb-Nb weld metals showed much higher fracture toughness than the small grain Nb. An extrapolation and comparison with existing data showed that the fracture toughness of the small grain Nb metals at 4 K was expected to be similar to those at 173 and 77 K. The results from optical photography at a low magnification and fractography by a scanning electron microscope were consistent with corresponding mechanical properties.
Original language | English |
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Pages (from-to) | 420-426 |
Number of pages | 7 |
Journal | Journal of Nuclear Materials |
Volume | 392 |
Issue number | 3 |
DOIs | |
State | Published - Aug 1 2009 |
Funding
The study was sponsored by US Department of Energy, Offices of Basic Energy Science, under Contract DE-AC05-00OR22725 with UT-Battelle, LLC. The authors thank E. Manischmudt and A.M. Williams for their efforts for DCT fracture testing and SEM fractography. The authors also express special thanks to Drs Isidoro E. Campisi and David A. McClintock for their thorough reviews and thoughtful comments.
Funders | Funder number |
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Basic Energy Science | DE-AC05-00OR22725 |
US Department of Energy |