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In situ x-ray diffraction study of the δ→α isothermal martensitic transformation kinetics in a Pu-Ga alloy

Journal Article · · Journal of Nuclear Materials
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  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Physical and Life Sciences Directorate
  2. Carnegie Inst. of Washington, Argonne, IL (United States). Geophysical Lab., High Pressure Synergetic Consortium (HPSync)
The sequence of phase formation and the isothermal kinetics of the δ to α' phase transformation in a Pu–1.9 at.% Ga alloy are investigated with in situ X-ray diffraction at the Advanced Photon Source. It has been proposed that the formation of a γ' intermediate phase may be responsible for the unusual double-C curve kinetics reported for this isothermal martensitic transformation. While a γ' intermediate phase was not observed at either -120 °C or -155 °C, an unexplained shoulder on the δ (1 1 1) peak was detected at -155 °C. The isothermal kinetics of the δ → α' transformation appear to fit a Johnson–Mehl–Avrami–Kolmogorov equation, but the exponent is not described by existing JMAK theory. The double-C curve kinetics of the δ to α' transformation remain unresolved in plutonium science, and understanding this behavior is key to predicting phase stability in aging Pu–Ga alloys.
Research Organization:
Energy Frontier Research Centers (EFRC); Energy Frontier Research in Extreme Environments (EFree)
Sponsoring Organization:
USDOE
DOE Contract Number:
SC0001057
OSTI ID:
1065544
Journal Information:
Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Journal Issue: 3 Vol. 412; ISSN 0022-3115
Publisher:
Elsevier
Country of Publication:
United States
Language:
English