Texture Analyses and Mechanical Behavior of a High-Mn Steel Subjected to Different Pass Number of Simple Shear

Abstract

The microstructural evolution of TWIP steels under high strain-induced microstructural refinement is complex and requires careful investigation. A FeMnCrC TWIP steel was effectively deformed by simple shear through the equal channel angular pressing (ECAP) technique at 350 °C up to eight passes, using route Bc. Microstructure characterizations of the as-received and ECAP-processed specimens were performed by means of X-ray diffraction, Scanning Electron Microscopy and Electron Back-Scattered Diffraction. The High-speed nanoindentation technique has been used to analyze the mechanical properties. The correlation between microstructure, texture orientation, and grain refinement was systematically investigated. After the first pass, the sample presented A1*, A2*, and C as the most potent components. Samples that experienced the highest number of passes presented the highest intensity of fiber B. After the ECAP cycle, the investigated steel presented a homogeneous ultra-fine-grained structure. Nanoindentation maps suggested isotropic mechanical properties. The metal showed a significant increase in yield strength and high Ultimate tensile Strength compared to the as received. The high density of mechanical twinning, reduced grain size, and subgrains contributed to increased mechanical properties. Additionally, the severe plastic deformation increased the strength of the metal due to the gradual transition from homogeneous to heterogeneous microstructure composed of shear bands, dislocations, and micro-twin colonies. The results show that using the ECAP deformation technology can improve the mechanical properties of TWIP steels and reveal that the investigated metal has excellent potential to be employed in industry. Graphical Abstract: (Figure presented.)