The role of carbon segregation on nanocrystallisation of pearlitic steels processed by severe plastic deformation.

Xavier Sauvage (1) , Yulia Ivanisenko (2)

1 GPM - Groupe de physique des matériaux
2 INT - Institut für Nanotechnologie [Karlsruhe]

The nanostructure and the carbon distribution in a pearlitic steel processed by torsion under high pressure was investigated by three-dimensional atom probe. In the early stage of deformation (shear strain of 62), off-stoichiometry cementite was analysed close to interphase boundaries and a strong segregation of carbon atoms along dislocation cell boundaries was observed in the ferrite. At a shear strain of 300, only few nanoscaled off-stoichiometry cementite particles remain and a nanoscaled equiaxed grain structure with a grain size of about 20 nm was revealed. 3D-AP data clearly point out a strong segregation of carbon atoms along grain boundaries. The influence of this carbon atom segregation on the nanostructure formation is discussed and a scenario accounting for the nanocrystallisation during severe plastic deformation is proposed.

Mots clés: severe plastic deformation; three-dimensional atom probe; pearlitic steels; nanocrystalline material; segregation.; segregation

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Xavier Sauvage, Yulia Ivanisenko. The role of carbon segregation on nanocrystallisation of pearlitic steels processed by severe plastic deformation.. Journal of Materials Science, 2006, 42, pp.1615. ⟨10.1007/s10853-006-0750-z⟩. ⟨hal-00276098⟩