Microstructure and texture evolutions in FeCrAl cladding tube during pilger processing

Autor: Xiao Qin, Ruiqian Zhang, Peinan Du, Jingyuan Pei, Qianfu Pan, Yu Cao, Huiqun Liu
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Journal of Materials Research and Technology, Vol 25, Iss , Pp 5506-5519 (2023)
Druh dokumentu: article
ISSN: 2238-7854
DOI: 10.1016/j.jmrt.2023.06.255
Popis: The microstructure of FeCrAl cladding tubes depends on the fabricating process history. In this study, the microstructural characteristics of wrought FeCrAl alloys during industrial pilger processing into thin-walled tubes were investigated. The hot extruded tube showed ∼100 μm equiaxed grains with weak α∗-fiber in {h11} texture, while pilger rolling process change the microstructure to fragmented and elongated grains along the rolling direction. The pilgered textures could be predicted with the VPSC model. The inter-pass annealing at 800–850 °C for 1 h results in recovery and recrystallization of the ferric matrix and restoration of ductility. The final finished tube shows fine recrystallized grains (∼11 μm) with dominant γ-fiber in three dimensions. Pilger rolling enhanced α-fiber while annealing reduced α-fiber and enhanced γ-fiber. Microstructural evolution in the Laves precipitates followed the sequence of faceted needle-like → spherical → faceted ellipsoidal. Thermomechanical processing resulted in cladding tubes with an area fraction of ∼5% and a number density of 5 × 10−11 m−2 in Laves precipitates, which is half that of the first-pilgered tube. Laves precipitates pin the grain boundaries to control the microstructure and prevent grain coarsening.
Databáze: Directory of Open Access Journals