CONICET | Buscador de Institutos y Recursos Humanos

The mechanical properties of a material are determined by its microstructure, therefore it must be subjected to certain thermomechanical processes that will confer it with the desired structure for its application. Severe Plastic Deformation techniques (SPD) (such as Equal Channel Angular Extrusion (ECAE) or Accumulative Roll Bonding (ARB)) produce high level of shear deformation, transforming the original structure into an arrangement of sub-micrometric or nanometric grains and dislocation cells. The analysis of the microstructure developed by a material can be achieved using X-ray diffraction technique, because the defects introduced in a material affect its diffraction pattern. The use of any of the micromechanical models that correlate the changes in the pattern and the microstructure lead to an estimation of dislocation and stacking fault density and average domain size. Some of the mentioned models are Williamson-Hall plot and Convolutional Multiple Whole Profile. For a complete analysis of the microstructure it is possible to use Electron Backscatter Diffraction (EBSD) which when implemented in a scanning electron microscope allows both the observation of the microstructure of the material and the evaluation of crystal orientation and misorientation on each point in the analyzed area, bringing information that complements the data observed using x-ray diffraction. This paper presents the analysis of the microstructure developed in an F138 steel deformed by ECAE and rolling. The information obtained using the techniques mentioned earlier allowed to understand the different stages of the deformation process, indentifying both analytically and graphically the presence an frequency of dislocation arrays and stacking faults.

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