Isothermal δ/α’ Transformation and TTT Diagram in a Plutonium Gallium Alloy


Differential scanning calorimetry (DSC) is used as an alternative approach to determining the time-temperature-transformation (TTT) diagram for the martensitic delta to alpha-prime transformation in a Pu-2.0 at% Ga alloy. Previous work sugests that the TTT diagram for a similar alloy exhibits an unusual double-C curve for isothermal holds of less than 100 minutes. Here, we extend this diagram to 18 hours, and confirm the double-C curve behavior. When the sample is cooled prior to the isothermal holds, the delta to alpha-prime transformation is observed as several overlapping exothermic peaks. These peaks are very reproducible, and they are believed to be the result of different kinds of delta to alpha-prime martensitic transformation. This may be due to the presence of different nucleation sites and/or different morphologies.

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Correspondence to B. J. P. Oudot.

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Oudot, B.J.P., Blobaum, K.J.M., Wall, M.A. et al. Isothermal δ/α’ Transformation and TTT Diagram in a Plutonium Gallium Alloy. MRS Online Proceedings Library 893, 8930502 (2005).

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