The effects of Cr and Nb on the microstructure, mechanical properties, and oxidation behavior of FeCrAl alloys

This article explores the effects of Cr and Nb on the microstructure, mechanical properties, and oxidation behavior in 1200°C steam of FeCrAl alloys. The experimental results indicate that Cr is solidly dissolved in the matrix, has minimal impact on the microstructure and mechanical properties. The addition of Nb leads to the precipitation of the Laves phase Fe 2 (Mo, Nb). The pinning effect of the Laves phase hinders the movement of grain boundaries and dislocations, thereby reducing grain size and increasing yield strength. Increasing the Cr content promotes the formation of Al 2 O 3 during the oxidation process of the alloy, which improves the adhesion of the oxide scale to the matrix and prevents its peeling. Additionally, higher Cr content results in a ridge-like morphology of the oxide film. The presence of the Laves phase effectively slows down the diffusion rate of ions, enhancing 1200°C steam oxidation resistance of FeCrAl alloys. This provides a basis for the in-depth development of FeCrAl alloys for nuclear fuel cladding.