Study of the Plastic Deformation in Nanocrystalline and Ultrafine Iron and Carbon Steels
Samples of nanostructured and ultrafine grained steels with carbon content ranging from 0.05 to 0.55%wt. have been obtained by a warm consolidation process from mechanically milled powders and subsequent heat treatments. In general, homogeneous grain size distributions were obtained except for the low-carbon steel in which a bimodal grain size distribution was observed when it was heat treated at high temperatures. The stress-strain response has been studied by means of compression tests. Nanostructured materials showed high strength but poor results in terms of ductility. In the low-ultrafine range (mean grain size between 100-500 nm) the three materials showed an increase in the ductility with strain softening. Finally, when the average grain size was close to 1 µm samples showed larger ductility and strain hardening.
Yuri Estrin and Hans Jürgen Maier
J. A. Benito et al., "Study of the Plastic Deformation in Nanocrystalline and Ultrafine Iron and Carbon Steels", Materials Science Forum, Vols. 584-586, pp. 617-622, 2008