Evolution of microstructure and mechanical properties of ZrC reinforced FeCrAl alloy after Fe-ions irradiation

FeCrAl alloy with high Cr content is prone to generate a large number of alpha' phases under irradiation condition at high temperature, which leads to hardening and embrittlement of the material and thus deterioration of its properties. In order to improve the radiation damage resistance of FeCrAl alloy in severe accident conditions, ZrC was added. In this paper, Fe13Cr3.5Al2.0Mo-1.0ZrC was irradiated with 400 keV Fe ions to 20 dpa at 400 degrees C (irradiation dose is 1.27 x 10(16) Fe+ / cm(2)). The ZrC reinforced FeCrAl alloy before and after irradiation was characterized by nanoindenter and Atom Probe Tomography (APT) technique. The results show that the nano-hardness increases from 5.78 GPa to 7.42 GPa after irradiation, and obvious irradiation hardening occurs. Diameter (d) and number density (N) of Zr-enriched domains, which play a role of reinforced phases, do not change obviously before and after irradiation. A large amount of fine MoC and alpha' phases are formed during irradiation. Formation of MoC is due to the enhanced diffusion of C and Mo (medium strong carbide forming element) induced by irradiation. Combining the experimental and calculation, the contribution of hardening by nano-precipitates irradiation-induced were investigated. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

FeCrAl alloy with high Cr content is prone to embrittlement and hardening under high temperature irradiation conditions due to the generation of alpha' phases. Adding ZrC can improve the radiation damage resistance of the alloy. The nano-hardness of the irradiated alloy increases significantly, and the formation of MoC and alpha' phases is observed.