Influence of dynamic strain ageing on ductile fracture of a C-Mn steel

Huaidong Wang (1, 2) , Clotilde Berdin (1) , Matthieu Mazière (3) , Samuel Forest (3) , Claude Prioul (1) , A. Parrot (2)

1 MSSMat - Laboratoire de mécanique des sols, structures et matériaux
2 EDF - EDF
3 CDM - Centre des Matériaux

Ductile fracture of a C-Mn steel was characterised by tensile tests performed in a largetemperature range (from 20 to 350°C) on round notched specimens. The experimentalresults revealed a sharp drop of fracture strain around 250°C. This corresponds to thedomain of dynamic strain ageing (DSA) occurrence. The Portevin-Le Chatelier (PLC) effect,which is the most classical effect of DSA, was modelled on round notched specimens with amechanical behaviour model including the strain ageing effect. Local approach to fracturewas applied to predict the ductile fracture using the Rice and Tracey criterion. Thepredictions are rather close to the experimental results for the low and high temperatures. Inthe DSA domain, the approach predicts a decrease of the fracture strain but with a lowermagnitude than the experimental one. Therefore, DSA has an effect on mechanical behaviour but also on fracture mechanisms. Consequently, the fracture criterion has to bemodified in the presence of DSA.

Mots clés: Dynamic strain ageing; ductile fracture; numerical modelling; local approach; Rice and Tracey criterion; strain localisation

Domaines: Matériaux

Huaidong Wang, Clotilde Berdin, Matthieu Mazière, Samuel Forest, Claude Prioul, et al.. Influence of dynamic strain ageing on ductile fracture of a C-Mn steel. Fracture of materials and structures from micro to macro scale - ECF 18, Aug 2010, Dresden, Germany. 8 p. ⟨hal-00541098⟩