A multi-scale study of the interaction of Sn solutes with dislocations during static recovery in α-Fe

N. Mavrikakis (1, 2) , C. Detlefs (3) , P.K. Cook (3) , M. Kutsal (3, 4) , A.P.C. Campos (5) , Melanie Gauvin (6) , P.R. Calvillo (6) , W. Saikaly (6) , R. Hubert (6) , H.F. Poulsen (7) , Antoine Vaugeois (8) , Helena Zapolsky (8) , D. Mangelinck (2) , M. Dumont (2) , C. Yildirim (3)

1 ArcelorMittal
2 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
3 ESRF - European Synchrotron Radiation Facility
4 Department of Physics [Lyngby]
5 AMU CP2M - Centre Pluridisciplinaire de Microscopie Electronique et de Microanalyse
6 OCAS - Centre de Recherche pour l'utilisation de l'Acier
7 DTU - Danmarks Tekniske Universitet = Technical University of Denmark
8 GPM - Groupe de physique des matériaux

The properties of engineering materials can be improved by optimising the microstructural developments during annealing processes. Here, we investigate the effect of Sn on the recovery annealing of cold rolled Fe-3%Si alloys. We use a multiscale approach combining micro hardness, electron back scattering diffraction (EBSD), and dark field X-ray microscopy (DFXM): a recent, nondestructive synchrotron-based technique that allows 3D mapping of orientation and lattice strain within individual grains embedded in bulk samples. Micro hardness results show that the Sn solute has a strong effect on the recovery kinetics. These results are compared to a physical kinetic model suggesting that Sn limits the softening. This observation is further discussed by a complementary atomistic modelling that demonstrates solute-dislocation interaction around edge dislocations. In situ DFXM experiments reveal the 3D microstructural evolution upon annealing at the grain level with high angular resolution. The DFXM observations show that Sn slows the recovery kinetics within individual grains, in agreement with the other microscopic investigations. Furthermore, the DFXM results provide a direct observation of strain fields around dislocation loops in an embedded single grain, which is argued to remain static due to solute effect during recovery.

Mots clés: ferrite; recovery; solute atom; dark field X-ray microscopy (DFXM); dislocation

Domaines: Matériaux

N. Mavrikakis, C. Detlefs, P.K. Cook, M. Kutsal, A.P.C. Campos, et al.. A multi-scale study of the interaction of Sn solutes with dislocations during static recovery in α-Fe. Acta Materialia, 2019, 174, pp.92-104. ⟨10.1016/j.actamat.2019.05.021⟩. ⟨hal-02403188⟩