Microstructure and radiation stability of nano-dispersoids in particle-reinforced FeCrAl alloys with different Zr concentrations

Recently, particle-reinforced FeCrAl alloys as one of the most promising candidates for accident tolerant fuel (ATF) materials in nuclear systems have attracted widespread attention. In this study, ZrC-reinforced FeCrAl alloys with different Zr concentrations were proposed and irradiated by 6 MeV Au3+ ions to 215 displacements per atom (dpa) at 350 ℃. The pristine alloys have three typical particles of coherent Al-O-riched dispersoids, Cr-carbides, and ZrC in the matrix. After ion irradiation, the density of nanoparticles decreases significantly while the average size increases. The changes of the dispersoids in ion-irradiated FeCrAl alloys are considered to be the competition results between the diffusion-dominated growth and the radiation-induced dissolution of the Al-O-riced dispersoids. It was found that the dispersoids exhibited unequal response in the alloys with different Zr concentrations under radiation. The radiation-induced destruction or dissolution of the dispersoids is significantly suppressed by Zr addition, which could be due to that Zr could lower the interfacial energy of dispersoids by transforming Al-O dispersoids to Al-Zr-O dispersoids, therefore improving their stability under radiation condition. These insights provide experimental basis for designing highly radiation tolerant particle-reinforced FeCrAl alloys, and contribute to the ongoing development for the particle-dispersoid-strengthened alloys for the nuclear applications.