The effect of He bubbles on the swelling and hardening of UNS N10003 alloy

In order to investigate the effect of He bubbles on the swelling and hardening of nickel based alloys, 1.2 MeV He ion irradiation was performed on UNS N10003 alloy at 650 °C. The number densities and sizes of He bubbles increase with increasing irradiation dose. Neither “black spots” nor dislocation loops were observed in TEM images of the as-irradiated samples. Irradiation dose up to 6.18 displacements per atom (dpa) causes a swelling of 2.67%, which is mainly ascribed to He bubbles. He bubbles induced hardening increases with increasing irradiation dose. The irradiation hardening behavior was compared with heavy ion irradiation. The result reveals that the obstacle strength of He bubbles is less than that of the saturated heavy ion induced irradiation defects.