Recrystallization and texture evolution of warm-pilgered FeCrAl alloy tube during annealing at 850°C

Journal article, 2022

Recrystallization annealing of warm-pilgered FeCrAl tubes was the key to reduce the cracking and control the microstructure and properties of the cladding tube. The recrystallization and texture evolution of warm-pilgered FeCrAl tubes were investigated. The recrystallization kinetics and textural evolution during annealing were characterized using microhardness measurements and electron backscatter diffraction. The 3D-microstructure of the warm-pilgered FeCrAl tube exhibited heterogeneous deformed grains of α-fiber and γ-fiber orientation. The significant anisotropy results in different recrystallization kinetics in the axial and circumferential directions of the tube. The mirostructure maintains a stable grain size of ∼22 µm and an aspect ratio of 1.8 in the axial and circumferential directions within 0–600 min annealing time. The stable microstructure is due to the dispersion of fine Laves phase particles in the ferrite matrix. Quantitative texture analysis shows that the α-fiber texture decreased significantly and the γ-fiber increased after recrystallization. During the annealing process, the α-fiber strong point texture component {112}<110> turns into {223}<110> and the γ-fiber component {111}<110> turns into {111}<112>. The recrystallization and texture evolution of warm-pilgered FeCrAl tube is of great significance to preparation and microstructure control of final cladding tube.