Study of Stress Partitioning in a 0.68 wt%C Pearlitic Steel Using High Energy X-Ray Synchrotron Radiation

Abstract

Abstract. In the present work, the evolution of the phase stresses in a 0.68 wt%C pearlitic steel is analyzed by synchrotron diffraction during uniaxial tensile loading, at room temperature. The diffraction measurements were done at ESRF beamline ID15B (Grenoble, France). The microstructure of the studied material, obtained after an austenitizing at 1050°C for 7 minutes followed by cooling under blowing air, corresponds to fully pearlitic steel with a cementite volume fraction of about 12.5%. As expected, the results show a clear effect of elastic and plastic anisotropy in the both phases. For the interpretation of the diffraction data, different models are compared. In elastic range and for small plastic deformation, the self-consistent model presents the best agreement with the experimental data. For large plastic deformation, this model does not predict correctly the stress partitioning between the phases as well as the macro behavior of the studied steel. Therefore a mixture model "(1-x)*self-consistent model + x*Taylor" was used to take into account the interaction between the phases. IntroductionOffering an excellent combination of ductility, strength and cost, the fully pearlitic steels are the most used plain carbon steels in manufacturing to produce wires for reinforcing tires, cables for suspension bridges, engineering springs for automotive and railroads. The role of the microstructure and specially the interlamellar space in the mechanical behavior and fatigue resistance of pearlitic steels has been studied in previous works [1,2]. In-situ diffraction technique during mechanical loading is a powerful method to investigate the mechanical behavior of the phases and the stress partitioning between the cementite and the ferrite [2][3][4][5]. Only few results concerning the role of the