Analysis of irradiation influence on M23C6 precipitates stability on grain boundaries in austenitic stainless steels

Theoretical investigation has been conducted into the influence of radiation induced segregation of basic components in stainless austenitic steels on stability of M23C6 carbides at grain boundaries. The absence of carbides along grain boundaries at irradiation temperatures lower 500-600 deg C is explained by essential chromium depletion in the vicinity of grain boundaries due to radiation-induced segregation. Analytical evaluation has been made for the irradiation temperature in excess of which the growth of M23C6 precipitations at grain boundaries becomes possible. This temperature has been found to decrease with the velocity of point defect generation as well as with an increase of carbon content in steel and dislocation sink intensity