Mechanical properties of FeCrMn-based steels are of major importance for practical applications. In this work, we investigate mechanical properties of disordered paramagnetic fcc FeCr 10 – 16 Mn 12 – 32 alloys using density functional theory. The effects of composition and temperature changes on the magnetic state, elastic properties and stacking fault energies of the alloys are studied. Calculated dependencies of the lattice and elastic constants are used to evaluate the effect of the solid solution strengthening by Mn and Cr using a modified Labusch-Nabarro model and a model for concentrated alloys. The effect of Cr and Mn alloying on the stacking fault energies is calculated and discussed in connection to possible deformation mechanisms.

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The aim of this work was to investigate the deformation mechanism in a highly alloyed austenitic Mn-steel, because these steels can deform by twinning and/or slip. Deformation by localized twinning or slip leads to formation of deformation structures on the surface, which are either bundles of deformation twins or slip bands. Such deformation structures around a standard Vickers hardness indent were investigated by means of scanning electron microscopy and electron backscatter diffraction to study the active deformation mechanism. Energy dispersive x-ray spectroscopy was conducted in order to study influences of segregation on the deformation.The main result of the investigations is that the deformation structures are formed by dislocation slip in the (101)-orientation and that an influence of segregations in the alloy composition on the deformation mechanism was not observed.