The effect of tungsten on microstructure and mechanical performance of an ultrafine Fe-Cr steel

Model Fe-Cr alloys with and without W were nanostructured by severe plastic deformation at 350˚C. Transmission electron microscopy observations of the microstructure indicate that the addition of 1 wt% of W led to a reduction of the mean grain size from 129 to 110 nm. Atom probe analyses show that only Cr and Si segregate at grain boundaries during deformation while W remains homogeneously distributed. This solid solution leads to higher mechanical strength and plasticity as compared to Fe-Cr. The origin of the beneficial effect of W on the mechanical performance is discussed.