Influence of silicon and phosphorus on radiation-induced segregation of chromium and nickel in austenitic model alloys

Abstract

The influence of undersized solute additions on radiation-induced segregation (RIS) at grain boundaries was examined for austenitic model alloys. High-purity Fe-15Cr-20Ni alloys, doped with either 0.5 mass% silicon or 0.025 mass% phosphorus, were exposed to electron irradiation at several temperatures in a high-voltage electron microscope. The grain boundary depletion of chromium and segregation of nickel were significantly suppressed by the addition of silicon and phosphorus, and the addition of phosphorus significantly reduced the RIS at a grain boundary. It was shown by numerical simulation that the present results stem from the strong interaction between the additives and interstitial atoms produced by the electron irradiation. © 2005 The Japan Institute of Metals.