Improvement of irradiation properties and environmental strengths of stainless steels by thermomechanical treatment SAR

Swelling behaviors of austenitic stainless steels (SS), which were treated thermodynamically so-called SAR (strained, aged and recrystallized), were studied through 1 MeV electron irradiation tests at 5000C up to 30 dpa. SAR-treated steels have a fine grain structure with stable precipitates dispersed uniformly in the refined matrix and are immune to the low temperature sensitization. Swelling rates of SAR-treated steels showed nearly ten times lower than that of solution treated steels. Difference of swelling rates among thermal controls is corresponding well to the sensitivity to sensitization and also the concentration of electron vacancies. Improvement of a resistance to void swelling by SAR treatment was interpreted based on refining effects that inhibit the additional bias effects caused by the chemical interaction between supersaturation solutes and radiation-induced defects. (orig.)