Abstract
The changes in microstructure and mechanical properties of Mo-41Re and Mo-47.5Re alloys were investigated following 1100 h thermal aging at 1098, 1248 and 1398 K. The electrical resistivity, hardness and tensile properties of the alloys were measured both before and after aging, along with the alloy microstructures though investigation by optical and electron microscopy techniques. The Mo-41Re alloy retained a single-phase solid solution microstructure following 1100 h aging at all temperatures, exhibiting no signs of precipitation, despite measurable changes in resistivity and hardness in the 1098 K aged material. Annealing Mo-47.5Re for 1 h at 1773 K resulted in a two-phase αMo + σ structure, with subsequent aging at 1398 K producing a further precipitation of the σ phase along the grain boundaries. This resulted in increases in resistivity, hardness and tensile strength with a corresponding reduction in ductility. Aging Mo-47.5Re at 1098 and 1248 K led to the development of the χ phase along grain boundaries, resulting in decreased resistivity and increased hardness and tensile strength while showing no loss in ductility relative to the as-annealed material.
| Original language | English |
|---|---|
| Pages (from-to) | 369-387 |
| Number of pages | 19 |
| Journal | Journal of Nuclear Materials |
| Volume | 366 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jul 1 2007 |
Funding
The authors would like to thank J. Hack, R. Baranwal, T.M. Angeliu and Y. Ballout of the Naval Reactors Prime Contractor Team for many helpful technical discussions and guidance. The authors would like to thank Marie Williams, Mike Pershing and Cliff Davison for help in acid cleaning and annealing of the specimens prior to thermal aging; Jeffrey McNabb and Bob Sitterson for welding and leak testing the Alloy 600 aging cans; Brian Sparks and David Harper for thermal aging the encapsulated materials; Kathy Thomas and Jackie Mayotte for their help in preparing samples for microscopy. The authors would also like to thank E.K. Ohriner and E.P. George for their helpful discussions. This work was performed under the sponsorship of NASA’s Project Prometheus and directed by DOE/NNSA Naval Reactors. Opinions and conclusions drawn by the authors are not endorsed by DOE/NNSA Naval Reactors. Research at the Oak Ridge National Laboratory SHaRE User Center was sponsored by the Division of Materials Sciences and Engineering, US Department of Energy. ORNL is managed for DOE by UT-Battelle, LLC, under contract DE-AC-05-00OR22725.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | |
| Division of Materials Sciences and Engineering | |
| UT-Battelle | DE-AC-05-00OR22725 |