Centre d’Élaboration de Matériaux et d’Etudes Structurales (UPR 8011)


Accueil > Recherche > PPM : Physique de la Plasticité et Métallurgie > Alliages métalliques à microstructure complexe

Structural work-hardening : martensitic steels

Microstructure and deformation mechanisms in last generation martensitic steels

Staff : Armand Coujou, Joël Douin, Florence-Pettinari-Sturmel, Vanessa Vidal

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(a) Image STEM dans l’acier ML1014. (b) Spectre EELS obtenu au point 1 (dans un carbure : présence importante du pic de Cr) et au point 2 (au sein de la matrice de Fer)
© CEMES-CNRS

This work, which is linked to the research program AMARAGE financially supported by the ANR (Agence Nationale de la Recherche), participates to the development of new high performance steels combining high mechanical resistance and improved toughness for aeronautic applications, in collaboration with the Aubert & Duval industrial group.

A double precipitation of carbides and intermetallic phases has been developed to increase the strength of the steels. This solution greatly improves the mechanical performance of steels.

Up to now, no fundamental research has been carried out in this area, which is just emerging, and a lot of fundamental investigations must be done.

 

As the mechanical properties are controlled by the interactions between the dislocations and the complex microstructure, an effort is made to obtain a precise characterization of the precipitation, the kinetic of this precipitation and of course the deformation micromechanisms associated with this precipitation. A better understanding of the precipitation and its effect on the mechanical properties is an essential step in the development of new generation steels.

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Image MEHR d’un carbure nanométrique (a) ; Cartographie des champs de déformation autour du carbure ; Image MEHR de plusieurs carbures (c).
© CEMES-CNRS
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Interaction dislocations / précipités : évidence de boucle de dislocations autour des nanoprécipités
© CEMES-CNRS