Cerium isomorphism and the δ–α transformation in plutonium

We use the thermodynamic model introduced by Aptekar’ and Ponyatovskiy for the γ–α transformation in cerium metal to study the properties of plutonium metal. The model describes the δ–α transformation in Pu and explains the minimum in the melting versus pressure curves for both materials. Ga stabilization of the δ-phase of Pu is explained in terms of a first order transition between the two phases. The model parameters found for Pu are similar to those found earlier for Ce.