Processability evaluation of a Mo-containing FeCrAl alloy for seamless thin wall tube fabrication

The processability of a Mo-containing FeCrAl alloy (Fe-13Cr-5.2Al-2Mo base, in wt%), developed for accident tolerant nuclear fuel claddings, was evaluated through a stepwise rolling process at 400 degrees C under two different inter-pass annealing conditions (i.e., 650 degrees C for 1 h and at 870 degrees C for 30 min). The inter-pass annealing at 870 degrees C easily softened the FeCrAl alloy; however, it led to the formation of coarse grains of 200 gm. On the other hand, the FeCrAl alloy maintained elongated, deformed grains with the inter-pass annealing at 650 degrees C, but the annealed samples showed relatively high deformation resistance and strong texture. Important aspects concerning the processability and microstructural control of FeCrAl alloys, such as deformation inhomogeneity, texture development, and grain coarsening, were discussed. Optimized processing conditions were recommended, based on the results, to achieve desirable microstructures with balanced processability and mechanical properties.