Radiation-damage in molybdenum-rhenium alloys for space reactor applications

J. T. Busby, K. J. Leonard, S. J. Zinkle

Research output: Contribution to journalArticlepeer-review

60 Scopus citations

Abstract

Various Mo-Re alloys are attractive candidates for use as fuel cladding and core structural materials in spacecraft reactor applications. Molybdenum alloys with rhenium contents of 41-47.5% (wt%), in particular, have good creep resistance and ductility in both base metal and weldments. However, irradiation-induced changes such as transmutation and radiation-induced segregation could lead to precipitation and, ultimately, radiation-induced embrittlement. The objective of this work is to evaluate the performance of Mo-41Re and Mo-47.5Re after irradiation at space reactor relevant temperatures. Tensile specimens of Mo-41Re and Mo-47.5Re alloys were irradiated to ∼0.7 displacements per atom (dpa) at 1073, 1223, and 1373 K and ∼1.4 dpa at 1073 K in the High Flux Isotope Reactor at Oak Ridge National Laboratory. Following irradiation, the specimens were strained to failure at a rate of 1 × 10-3 s-1 in vacuum at the irradiation temperature. In addition, unirradiated specimens and specimens aged for 1100 h at each irradiation temperature were also tested. Fracture mode of the tensile specimens was determined. The tensile tests and fractography showed severe embrittlement and IG failure with increasing temperatures above 1100 K, even at the lowest fluence. This high temperature embrittlement is likely the result of irradiation-induced changes such as transmutation and radiation-induced segregation. These factors could lead to precipitation and, ultimately, radiation-induced embrittlement. The objective of this work is to examine the irradiation-induced degradation for these Mo-Re alloys under neutron irradiation.

Original languageEnglish
Pages (from-to)388-406
Number of pages19
JournalJournal of Nuclear Materials
Volume366
Issue number3
DOIs
StatePublished - Jul 1 2007

Funding

The authors would like to thank J.L. Bump, J.E. Hack, E.V Mader, R.J. Nelson, and G.A. Newsome of the Naval Reactors Prime Contractor Team for many helpful technical discussions and guidance. The authors would also like to thank L.L. Snead, C.E. Duty, and especially F.A. Garner and F.W. Wiffen for many helpful discussions. Experiments involving reactor-irradiated materials are complex and require assistance from many different people. The authors would like to thank E. Ohriner, J. Mayotte, M. Williams, J. McDuffee, B. Sitterson, G. Hirtz, R, Stoller, S. Meyers, P. Bishop, J. Bailey, H. Phillips, P. Tedder, L. Gibson, J. Gardner, and R. Jones for their assistance. This work was performed under the sponsorship of NASA’s Project Prometheus and directed by the US Department of Energy/National Nuclear Security Administration (DOE/NNSA) Naval Reactors. Opinions and conclusions drawn by the authors are not endorsed by DOE/NNSA Naval Reactors. ORNL is managed for DOE by UT-Battelle, LLC, under Contract DE-AC-05-00OR22725.

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