Mechanical properties, 475°C embrittlement and irradiation resistance of FeCrAl-Y2O3 ODS alloy with Ti and V alloying additions

Abstract

FeCrAl-based ODS alloys are promising for Generation IV nuclear reactor components since they present remarkable properties, such as high mechanical strength and good irradiation resistance. However, there is still relatively little information on the impact of minor alloying elements, e.g., Ti or V, and manufacturing conditions on the properties of these alloys. In this paper, two FeCrAl-based alloys with the minor addition of Y₂O₃, Ti, and V were studied. The investigation focuses on the mechanical properties at high temperatures (up to 800 °C), resistance to so-called “475 °C embrittlement” (α and α’ phase separation), and irradiation resistance. The conducted tensile tests show promising mechanical properties at room temperature, i.e., the yield strength is 893±23 MPa, and the ultimate tensile strength is 993±10 MPa. The tensile tests at high temperatures also confirm good properties, e.g., at 600 °C the yield strength is 490±8 MPa, the ultimate tensile strength is 526±14 MPa, while the total elongation is 17±4 %. The results reveal that adding vanadium increases the strength of the FeCrAl ODS alloys. The conducted annealing at 475 °C for 1000 h shows limited hardening and almost no change in elongation of the alloy with the addition of vanadium. The performed ion irradiation experiments show good irradiation resistance of both tested alloys, manifesting by limited hardening and stable oxide precipitates. The results confirm the promising properties of studied materials for application in the nuclear industry, particularly in Generation IV reactors. Moreover, the results show the possibility of tuning properties by adding alloying elements, such as vanadium.