par Godet, Stéphane ;Jacques, Patrice;Delannay, F.
Référence (07.11.2000 - 09.11.2000: Tours, France), Advances in Mechanical Behaviour, Plasticity and Damage, Vol. 2, page (835-840)
Publication Publié, 2000
Publication dans des actes
Résumé : This study deals with the hot deformation of TRIP-assisted multiphase steels. These steels consist typically of bainite and retained austenite grains dispersed in a ferritic matrix. The austenite, which is metastable at room temp., transforms to martensite during straining, bringing about the TRIP effect, which improves the strength-ductility balance of these steels. This work studies the effect of a prior deformation in the intercrit. temp. range on the mech. properties and work hardening behavior of these TRIP-assisted multiphase steels. Several deformation levels in the ferrite-austenite domain were applied during the thermomech. scheme. Work-hardening is strongly enhanced when the specimens were sufficiently deformed in the intercrit. temp. range. This study also shows that the beneficial influence of the prior deformation is more related to the TRIP phenomenon than to the strain-hardening of the ferritic matrix. These expts. prove that a displacive transformation such as the martensitic transformation is highly influenced by the dislocation d. within the parent phase.