On the constitutive relations for δ → α and α → δ martensitic transformation plasticity in plutonium alloys

Abstract A constitutive model for transformation plasticity based on isothermal martensitic kinetics is applied to δ → α and α → δ transformation in Pu alloys. The model is in good agreement with available data for the α → α transformation plasticity behavior of PuGa alloys in uniaxial compression as a function of composition, temperature and strain rate. Application to α → δ transformation in uniaxial tension and crack-tip stress states indicates that general transformation in uniaxial tension is precluded by premature brittle fracture of the α phase, but localized transformation will occur at crack tips as supported by metallographic observations.