Microstructure of Au-ion irradiated 316L and FeNiCr austenitic stainless steels

Thin foils of 316L were irradiated in situ in a Transmission Electron Microscope with 4 MeV Au ions at 450 degrees C and 550 degrees C. Similar irradiations were performed at 450 degrees C in FeNiCr. The void and dislocation microstructure of 316L is found to depend strongly on temperature. At 450 degrees C, a dense network of dislocation lines is observed in situ to grow from black dot defects by absorption of other black dots and interstitial clusters whilst no Frank loops are detected. At 550 degrees C, no such network is observed but large Frank loops and perfect loops whose sudden appearance is concomitant with a strong increase in void density as a result of a strong coupling between voids and dislocations. Moreover, differences in both alloys microstructure show the major role played by the minor constituents of 316L, increasing the stacking fault formation energy, and possibly leading to significant differences in swelling behaviour. (C) 2016 Elsevier B.V. All rights reserved.