In the hot deformation of the duplex stainlesssteels, the complexity of the microstructure evolution andmechanical response is increased as compared with those ofsingle-phase ferritic or austenitic stainless steels. In the presentwork, plane strain compression and torsion deformation modeshave been used to analyze the microstructural evolution andthe mechanical behavior of a duplex stainless steel in as-castand wrought conditions, as a function of spatial phasedistribution, the nature of interface, and the relative mechanicalproperties of both phases. The law of mixtures has been used toexplain the different flow cures obtained when changing thephase distribution and/or the deformation mode. On deformingas-cast microstructures, the deformation partitions varyheterogeneously between both phases and some austenite areasact as hard nondeforming particles. Cracks have been observedto occur at the interface of such regions, from relatively lowstrains, for which the initial Kurdjumov-Sachs orientationrelationship between ferrite and austenite is still present.
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