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

• Published in: Materials letters 2018-09, Vol.227, p.292-295
• Main Authors: Mazilkin, A., Abramova, M.M., Enikeev, N.A., Lomakin, I.V., Valiev, R.Z., Ivanisenko, Yu, Kübel, C., Etienne, A., Sauvage, X., Radiguet, B.
• Format: Article
• Language: English
• Subjects: Alloy steels; Chromium steels; Condensed Matter; Ferritic stainless steel; Ferritic steels; Ferrous alloys; Grain boundaries; High pressure torsion; Iron; Materials Science; Mechanical properties; Metals; Microstructure; Nanostructured materials; Physics; Plastic deformation; Silicon; Solid solutions; Transmission electron microscopy; Tungsten
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2018.05.098

•Fe-14Cr and Fe-14Cr-1 W alloys (wt%) were nanostructured by high pressure torsion.•Addition of W led to formation of smaller but more elongated ultrafine grains in Fe-Cr.•Ultrafine-grained Fe-Cr exhibited higher strength and plasticity with W alloying.•Ultrafine-grained Fe-Cr-W demonstrated better thermal stability than Fe-Cr. 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.