Dislocation loops and hardening induced by Au ion irradiation in FeCrAl alloys with three solute concentrations

Abstract

Three alloys, Fe-9Cr-6Al, Fe-11Cr-6Al and Fe-13Cr-4.5Al, were irradiated with 6 MeV Au+ ions to show their irradiation effect in this work. Statistics of the density and size of dislocation loops were performed in TEM images and 〈100〉 and 1/2 〈111〉 dislocation loops were treated differently. Irradiation hardening was measured by nanoindentation and hardness curves were analyzed by the Nix-Gao model. The DBH hardness was calculated by using statistical data of dislocation loops and lines. The results show a defect evolution of “dots to loops to lines” is clear as the damage dose increases from 5 to 20 dpa, the number and size of dislocation loops are increased with increasing the temperature to 400 °C at 10 dpa, and simultaneously, the irradiation hardening is enhanced. The Nix-Gao bulk equivalent, measured and DBH-calculated hardness curves are basically consistent in trend but decreases sequentially in numerical value. The loops-hardening mechanism is also discussed. Furthermore, an increase of the Cr content tends to reduce the density of dislocation loops, especially for the 400 °C irradiation and the alloy with 13 % Cr indeed show a good irradiation stability.