Phase-field simulation of dose rate effect on the Cu precipitation with neutron irradiation.

Radiation-enhanced precipitation (REP) of Cu in Fe-Cu alloys results in hardening and degradation of the mechanical properties. By combining the CALPHAD-based free energy for phase-field modeling, and radiation-enhanced diffusion (RED) with neutron irradiating energetic particle, the precipitation of Cu in binary Fe-Cu alloys is studied under different dose rates, concentrations, and temperatures. Rate theory (RT) provides the RED that serves as an input parameter for the phase-field simulation to capture the morphology of the precipitates. The REP results agree with the theoretical predictions: the increase in the dose rates increases the concentration of defects, and accelerates the kinetics of precipitation. The simulation predicts the stability of the precipitates even under high damage rates. The increase in radius is achieved for high damage rates. Precipitate dissolution is observed to be dependent on the combination of dose rate, concentration, and temperature. The work also outlines the limitations of the model and the potential future improvements.