Time-resolved evolution of the deformation mechanisms in a TRIP/TWIP Fe50Mn30Co10Cr10 high entropy during tensile loading probed with synchrotron X-ray diffraction

Abstract

The present research focuses on analyzing the deformation mechanisms associated with tensile loading of the Fe₅₀Mn₃₀Co₁₀Cr₁₀ high entropy alloy (HEA) using synchrotron x-ray diffraction (SXRD). This novel material is comprised by two major phases: γ-FCC and ε-HCP, where transformation induced plasticity (TRIP) effectively transforms the first into the latter, upon the application of an external stress. However, the presence of thermally stable ε-HCP prior to loading will also influence the deformation mechanism of the material during mechanical solicitation. As such, here we investigate the activation of different strain accommodation mechanisms and the consequent microstructural evolution. Four stages were identified in the mechanical response of this novel HEA, where the TRIP and the twinning induced plasticity (TWIP) deformation modes are the main events granting this HEA its outstanding properties. Such sequence of events allows to evidence the effectiveness of the collaboration between the transformative capability of the γ-FCC phase and the work hardening potential of the ε-HCP phase. This analysis is performed via quantitative and qualitative analysis of the SXRD data, allowing also to investigate the response behavior of specific crystallographic planes to the increasing stress throughout the experiment.