Radiation stability of the ODS alloys against swift heavy ion impact

The microstructure of Cr16 ferritic steel reinforced with yttrium oxide particles and KP4 ODS alloy irradiated with 167 MeV xenon and 700 MeV bismuth ions at 300 K has been studied using high resolution transmission electron microscopy. Amorphous latent tracks were identified in (Cr, W)23C6, Y2Ti2O7 and Y2TiO5 nanoparticles in Cr16 at a Bi ion fluence of 1.5 × 1012 cm−2. It was found that multiple track overlapping leads to complete amorphization of carbide and (Y, Ti) oxide particles in Cr16 specimens. No latent tracks have been observed in Y4Al2O9 particles in KP4 irradiated with Bi ions. Small oxide particles (∼5 nm), in KP4 alloy, remain crystalline at Bi ion fluences up to 1.5 × 1013 cm−2, while subsurface regions in large (∼20 nm) particles were amorphized. Xe ion irradiation at fluences of 1 × 1014 cm−2 and 1.5 × 1015 cm−2 resulted in amorphization of small Y4Al2O9 oxide particles while the amorphous bodies of large particles were found to contain small crystalline inclusions.