Optical Measurements, Modeling, and Metrology, Volume 5

Abstract

The high manganese TWIP (twinning induced plasticity) steels exhibit very high mechanical properties compared to others grades. Indeed they have a mechanical strength that can attain 1.5 GPa and fracture strain that can go up to 60%. However the governing damage mechanisms that maximize their ductility are not well understood. To have a better understanding of these mechanisms, in situ tensile tests have been carried out at the European Synchrotron Radiation Facility. During tensile test no necking can be observed which has already been observed on this type of steel. Moreover, the number of cavities in a given volume do not deeply evolve during the deformation meaning that nucleation of voids is weak in the TWIP steel considered. This leads to a maximal number at fracture very low compared to other steels (interstitial free steel, dual phase,...). Morever, the growth of cavities according to local strain seems to be equivalent to other austenitic or ferritic steels. At last, shear bands can be observed in the sample which seems to be correlated with some of the cavities.