A comparative study of the microstructural stability and magnetic properties of two Fe-Mn-C (1,5%Mn and 17%Mn) steels

Abstract

In this project, the microstructural evolution and magnetic properties of two Fe-Mn-C (1,5%Mn and 17%Mn) steels will be investigated. For these steels the TRIP effect (Transformation-Induced Plasticity) is expected to occur with high intensity for the one with lower content of manganese. The main focus of this work will be on the strain induced martensite (and its reversion). Besides, the thermally induced martensite will be also investigated. The two steels will be cold rolled and, in addition, annealed at high temperatures (up to 1000oC). The samples will be characterized using Vickers microhardness tests, conventional X-ray diffraction (macrotexture), light optical microscopy (LOM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), dilatometry, and both ex situ and in situ magnetic measurements. The in situ magnetic measurements will be obtained during the annealing and cooling of the material (up to cryogenic temperatures). From the magnetic measurements, besides de saturation magnetization (Ms), the behavior of the coercive field (Hc) will be also evaluated. Possible anisotropy effects in the martensite induced by rolling will be also investigated using dilatometry and magnetic measurements. In situ X-ray diffraction will be also performed during uniaxial tensile deformation of the material in order to evaluate the phase transformation induced by plastic deformation. The analysis of the undeformed material using EBSD and ARPGE software will lead to the reconstruction of the parent austenite grain structure.