MICROPLASTICITY OF MMC - EXPERIMENTAL RESULTS AND MODELING

The microplastic behavior of several MMC is investigated by means of t ension and compression tests. This behavior is assymetric : the propor tional limit is higher in tension than in compression but the work har dening rate is higher In compression. These differences ate analysed i n terms of maxium of the Tresca's shear stress at the interface (propo rtional limit) and of the emission of dislocation loops during the coo ling (work hardening rate). On another hand, a model is proposed to ca lculate the value of the yield stress, describing the composite as a m aterial composed of three phases : inclusion, unaffected matrix and ma trix surrounding the inclusion having a gradient in the density of the thermally induced dilocations.