Investigation of retained austenite stability in Mn-Si TRIP steel in tensile deformation condition

Purpose: The aim of this study is to contribute to a better understanding of the role of the key factors governing the formation of multiphase TRIP aided steel. Design/methodology/approach: The present work reports the results of in-situ neutron diffraction experiments focused on monitoring the phase evolution in three TRIP steel samples subjected to different thermomechanical processing and mechanical loading to evaluate the stability of retained austenite. Findings: In-situ neutron diffraction experiments allowed characterizing the elastoplastic properties of the phases present in TRIP steel. These properties have strong influence on the transformation behaviour of the retained austenite during the straining and also critical effect on general mechanical properties of TRIP steel. Research limitations/implications: The precise, fast and cheap measurement of the amount of retained austenite in multiphase structure is a basic limitation for further research work, improvement and development control of TRIP steels. Practical implications: It is believed that not only the sufficient volume fraction of the retained austenite is the prerequisite to achieve convenient conditions for TRIP effect in low-alloyed steels. Originality/value: It was found that not only volume fraction of retained austenite has the influence on mechanical properties of TRIP steels, but also the state (size, distribution, carbon saturation, morphology) of retained austenite and the state of surrounding (α-matrix) plays important role.