Article ID Journal Published Year Pages File Type
1613207 Journal of Alloys and Compounds 2013 12 Pages PDF
Abstract

•Direct δ-to-α′ phase transformation at low temperatures without any γ′ phase.•Competition between direct and indirect reversion at the first stage of reversion.•Involvement of Ga diffusion associated with indirect reversion mode.•Pure-Pu β and γ phases emergence during indirect reversion with δ-phase Ga enrichment.•Reversion process of PuGa 1 at.% alloy following martensitic transformation.

The purpose of this work was to study PuGa 1 at.% alloy behavior from martensitic transformation to the whole reversion process. The relevant phase transformations were investigated as a function of temperature via in situ X-ray diffraction and dilatometry analyses carried out at low and high temperatures. The results show that the δ-to-α′ martensitic transformation occurring at low temperatures is direct and does not involve any intermediate γ′ phase. They also reveal that the reverse transformation of the two-phase δ + α′ alloy during heating involves two competing modes, namely direct and indirect reversion. The latter is associated with a Ga diffusion process that governs the ratio between these reversion modes. More precisely, our study demonstrates that the indirect reversion process consists of a Ga-enrichment of the remaining δ phase as well as the emergence of the β and γ phases of pure plutonium. Every stage of indirect reversion has been discussed in relation to the equilibrium phase diagram of the Pu–Ga binary system.

Related Topics
Physical Sciences and Engineering Materials Science Metals and Alloys
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