Abstract
To explore the effects of aging and irradiation on the formation of solute clusters, Fe-2.8Ni-2.0Al (at.%) alloys after solid-solution treatment were aged at 500 ℃ for 16 h and 32 h and irradiated with Ar ions to the fluence of 4 × 1016 ions·cm−2 at 290 ℃, respectively. Transmission electron microscope and atom probe tomography were used to characterize the microstructure and solute atoms distribution. Results showed that B2-NiAl clusters were formed in aged alloys and the number density increased with time. The number density of clusters was 8.35 × 1022 m−3 after 32 h at 500 ℃ aging. However, high number density of dislocation loops and B2-FeNi clusters were found after irradiation at 290 ℃. The number density of clusters reached to 3.61 × 1023 m−3. The nucleation of B2-NiAl clusters under aging is driven by the phase transform free energy with the lower mixing enthalpy of Ni and Al atoms, while the formation of B2-FeNi clusters is due to the combination of the interaction between dislocation loops and Ni solutes with the enhanced diffusion rate of Ni atoms due to supersaturated vacancy.
Published Version
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