Micromechanics of high temperature deformation and failure

The micromechanics of the constitutive behavior of elastoplastic materials at high temperatures was examined. The experimental work focused on the development of microscopic defects in superalloys (Waspaloy), especially the formation of voids at grain boundary carbides, and slip induced surface cracks within grains upon cyclic loading at high temperatures. The influence of these defects on the life expectancy of the material was examined. The theoretical work consists of two parts: (1) analytical description of the mechanisms that lead to defects observed experimentally; and (2) development of macroscopic elastoplastic nonlinear constitutive relations based on mechanical modeling

Influence of stress state and strain path on deformation induced martensitic transformations

The mechanically induced transformation behavior of 12Crsingle bond9Nisingle bond 4Mo (ASTM A 564) austenitic stainless steel is investigated in different stress states. This phenomenon is studied experimentally on a plane-stress biaxial test facility. The facility can load a sheet specimen simultaneously in shear and tension which enables us to investigate the effect of stress state on transformation kinetics. The martensite fraction is monitored via a magnetic sensor while the strain is measured using a camera and a dot-tracking software

Formation à la recherche dans l’aire océanienne (FRAO)

Alban Bensa et Jonathan Friedman, directeurs d’étudesBrigitte Derlon, maîtresse de conférences avec Marie Pineau-Salaün Le séminaire a abordé quatre thèmes. Dans le premier d’entre eux, « L’institutionnalisation des mouvements politiques océaniens », coordonné par J. Friedman, A. Bensa a retracé les discours et pratiques des leaders nationalistes kanak entre 1950-2003 ; A. Babadzan a fait une présentation des processus d’institutionnalisation de la revendication maorie ; T. Van Meijl (Univers..