Advanced austenitic stainless steels combining high strength (1 GPa) and high ductility (> 60% strain) exhibit various deformation mechanisms, depending on temperature (cf. Fig. 1), strain rate and load condition. The low stacking fault energy of the fcc austenite enables prominent conditions for an extended range of dislocation single slip. Stacking fault formation during deformation involves the formation of twins, ε-martensite and produces nucleation sites for α’-martensite. While the formation of twins and ε-martensite mainly enhances the ductility, the formation of α’-martensite is responsible for increased strength. In this contribution, the work hardening due to martensitic transformations is discussed together with additional (V,Cr)N precipitation strengthening and solid solution hardening by interstitial C and N. Supported by the results of microstructure analyses using SEM, TEM and XRD that were carried out on as-produced and deformed samples, the influence of these additional strain hardening processes on the mechanical properties and on the changes in the deformation mechanism are assessed.
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|Poster||Figure 1||Deformation mechanisms as a function of deformation temperature and stacking fault energy for austenitic 16Cr6Mn6Ni steel||471 KB||Download|