Article Dans Une Revue Acta Materialia Année : 2025

Investigation of the influence of manganese on the dynamic strain ageing of ferritic steels – Part I: Model alloy

Résumé

Dislocation dynamics were studied in a ternary Fe-Mn-C model steel by in-situ tensile tests in a transmission electron microscope (TEM) at temperatures ranging from 300 K to 900 K. The influence of carbon and manganese on dynamic strain aging (DSA) is investigated, the latter being identified by a change in dislocation dynamics. In the DSA temperature range, plastic deformation proceeds by dislocation bursts or dislocation viscous glide. We measure dislocation glide velocities in the DSA regime to extract activation energies for dislocations glide. In Fe-C alloys, the activation energy for the so-called "high-temperature diffusion-controlled" (HTDC) Peierls glide of screw dislocations is close to the diffusion energy of carbon. Surprisingly, HTDC-Peierls glide of screw dislocations is not observed in Fe-Mn-C and viscous glide of mixed dislocations occurs at higher temperature with an activation energy close to that of Mn diffusion. We thus conclude that Mn addition hinders the HTDC-Peierls glide expected at about 500 K, and suggest that this may result from Mn being able to co-segregate with carbon on dislocations at temperatures as low as 500 K. In addition, Mn is responsible for DSA and controls dislocation viscous glide in the model Fe-Mn-C alloy. We propose a mechanism for Mn enrichment on mixed dislocations at such low temperatures, based on Mn pipe-diffuson. These findings shed new light on the elementary mechanisms controlling DSA in ferritic steels with a particular focus on the effect of C and Mn.

Fichier principal
Vignette du fichier
Fe-Mn-model.pdf (13.8 Mo) Télécharger le fichier
Origine Publication financée par une institution
Licence

Dates et versions

hal-05218692 , version 1 (22-08-2025)

Licence

Identifiants

Citer

W. Mottay, D. Caillard, H. Idrissi, P. Maugis, A. Portavoce, et al.. Investigation of the influence of manganese on the dynamic strain ageing of ferritic steels – Part I: Model alloy. Acta Materialia, 2025, 299, pp.121446. ⟨10.1016/j.actamat.2025.121446⟩. ⟨hal-05218692⟩
688 Consultations
119 Téléchargements

Altmetric

Partager

  • More