Consequences of Deep Rolling at Elevated Temperature on Near-Surface and Fatigue Properties of High-Manganese TWIP Steel X40MnCrAl19-2

Due to pronounced work-hardening induced by the complex interplay of deformation mechanisms such as dislocation slip, twinning and/or martensitic phase transformation, high-manganese steels represent a class materials well-suited for mechanical surface treatment. In present study, fatigue behavior high-mangsanese steel showing twinning-induced plasticity (TWIP) effect at room temperature (RT) was investigated after deep rolling 550 °C. Results are compared former study discussing RT rolling. Evolution near-surface microstructure analyzed scanning electron microscopy (SEM), microhardness measurements and residual stress depth profiles obtained X-ray diffraction (XRD). Both uniaxial tensile tests tension-compression have been conducted in order rationalize macroscopic material behavior. Following °C, SEM employing backscatter (EBSD) revealed heavily deformed layer well localized twinning. Specimens showed inferior hardness when rolled counterparts. Tensile indicated no difference between conditions considered. Fatigue properties however were improved. Such is rationalized more stable state dynamic strain aging.