Fig. 6: Semi-coherent phase diagrams of Fe–Ni is driven by irradiation.
From: Thermodynamic model for lattice point defect-mediated semi-coherent precipitation in alloys
Equilibrium (a) and radiation-induced metastable phase diagrams (b, c, d) of Fe–Ni including an SIA accommodation mechanism of the precipitate eigenstrain. In (c), part of the eigenstrain produced by the decomposition of phase γ is released by an elastic strain ensuring a coherent (100) interface. The γm-γ two-phase domain widens from (c) to (d), due to the release of the coherency constraint. At low and high radiation dose rates, the temperature-dependent atomic fraction of SIAs is respectively equal to cI = 10−20 m2 s−1/dI and cI = 10−14 m2 s−1/dI, where cI and dI are the atomic fraction and diffusion coefficient of SIAs. The product dIcI is related to the radiation flux and the overall annihilation strength of the microstructure acting as sinks of point defects (cf the “Methods”). The dotted-dashed line and gray dashed line are respectively for the Curie temperature and the spinodal limit. In temperature domains at which there are no experimental lattice parameters, boundary limits are plotted as dashed lines. Full symbols are the nominal compositions and open symbols are the compositions of the precipitated and parent phases measured after irradiation. Circles are for the radiation-induced bcc-fcc phase transformation and squares are for the spinodal decomposition of austenite irradiated with neutrons50 at 600 °C.
