Effect of heavy ion irradiation on the electrochemical behavior of 321 stainless steel

Abstract

Aiming to the environment for 321 stainless steel (SS) in primary circuit of pressurized water reactor (PWR), the effect of heavy ion irradiation to simulate neutron irradiation on the electrochemical behavior of alloy is unclear. The purpose of this work is to evaluate the corrosion resistance of 321 SS at different doses and the contribution of heavy ion irradiation in it. This work reveals that the corrosion resistance decreases in the order of 2 dpa > 0 dpa > 10 dpa > 60 dpa at room temperature, consistent with the sequence of δ-phase content near the surface. The effect of irradiation dose on the corrosion resistance of 321 SS is inversely proportional at higher dose and optimal performance of the SS irradiated to 2 dpa is attributed to the highest content of Cr-rich δ-phase. The pits occur in C enrichment zone, accompanied by increase of O content, while no pit occurs in Ti enrichment area. The results provide a reference for the irradiated SS with heavy ion to acquire optimal pitting resistence.