Dose rate dependence of Cr precipitation in an ion-irradiated Fe18Cr alloy

Abstract Precipitation of α′ in Fe Cr alloys under neutron irradiation is thermodynamically driven while being accelerated by radiation-enhanced diffusion. However, similar alloys under ion irradiation at high dose rates (> 10 − 4  dpa/s) fail to exhibit α′ precipitation. Here, the microstructure of an Fe 18Cr alloy under ion or neutron-irradiation at 300 °C at dose rates from ~ 10 − 7 to 10 − 4  dpa/s was analyzed by atom probe tomography. The steady-state composition content of the clusters depends on the ion irradiation dose and dose rate, confirming the contribution of ballistic mixing in diluting the Cr concentration in non-equilibrium α′ precipitates.