Radiation-induced shear bands enhance softening 316LN austenitic stainless steel

Radiation hardening is usually a major concern for materials used for nuclear reactors. Here, we report that helium (He) radiation could weaken the radiation hardening effect and even soften 316LN austenitic stainless steel by forming shear bands. The experiment results showed that the nanohardness of the steel decreased sharply after radiation by 200 keV He ion to a fluence of 2.3 × 1021 ions/m2. Moreover, it is noteworthy that the number and spacing of shear bands can be controlled indirectly by forming the radiation bubbles with appropriate size and distribution, which is hopeful to extend the application of He bubble engineering.