Recovery of Ductility in Ultrafine-Grained Low-Carbon Steel Processed Through Equal-Channel Angular Pressing Followed by Cold Rolling and Flash Annealing

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2017-03, Vol.48 (3), p.1189-1203
• Main Authors: Singh, Raj Bahadur, Mukhopadhyay, N. K., Sastry, G. V. S., Manna, R.
• Format: Article
• Language: English
• Subjects: Annealing; Cementite; Characterization and Evaluation of Materials; Chemistry and Materials Science; Cold rolling; Ductility; Equal channel angular pressing; Ferrite; Grains; Low carbon steel; Materials Science; Metallic Materials; Metallurgy; Nanotechnology; Steel alloys; Structural Materials; Surfaces and Interfaces; Texture; Thin Films; Yield strength
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-016-3892-x

The low-carbon steel workpieces are deformed by equal-channel angular pressing at 293 K (20 °C) up to an equivalent strain of ~12 using route B c , which results in the bulk ultrafine-grained (UFG) structure with high dislocation density and partial dissolution of cementite. The yield strength (YS) is enhanced from 208 (as-received) to 872 MPa and the tensile strength is increased from 362 to 996 MPa, but the material loses total elongation (TE) from 36.2 to 2.9 pct. Cold rolling of equal-channel angular pressed steel produces the refined structure of grain size 0.11  μ m. The YS increases further to 924 MPa with a marginal gain in ductility due to the reappearance of the γ fiber component. Flash annealing the samples, which were equal-channel angular pressed followed by cold rolling, at 873 K (600 °C) results in 27 pct of micron-sized (9  µ m) ferrite grains in submicron-sized (