Segregation of lutetium and yttrium to grain boundaries in iridium alloys
- Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.
- Auburn Univ., AL (United States). Materials Engineering Program
The equilibrium segregation of lutetium and yttrium to grain boundaries in iridium alloys containing 0.3 wt% tungsten was studied. The segregation level of Lu decreased with increasing annealing temperature whereas that of Y initially increased with increasing temperature but then decreased with further increases in temperature. At all temperatures, Y segregated more strongly than lutetium. The observed segregation behavior of the two dopants was explained on the basis of their free energies of segregation and solid solubilities, and the solvus lines for Lu and Y were obtained from the results. Energies of segregation and energies of solution for Lu and Y in the iridium alloy were also determined. Iridium alloys containing nominally 0.3 wt% W, 60 wppm Th and 50 wppm Al are used to clad the plutonia fuel pellets used in radioisotope thermoelectric generators for space power applications.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 599857
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 3 Vol. 46; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
FUEL CANS
GRAIN BOUNDARIES
IRIDIUM ALLOYS
LUTETIUM ADDITIONS
METALLURGICAL EFFECTS
NESDPS Office of Nuclear Energy Space and Defense Power Systems
RADIOISOTOPE BATTERIES
SEGREGATION
THERMOELECTRIC GENERATORS
YTTRIUM ADDITIONS