Tensile Behavior of Ferrite-Carbide and Ferrite-Martensite Steels with Different Ferrite Grain Structures

Ferrite-carbide and ferrite-martensite dual-phase microstructures have been produced in a low-carbon steel with different ferrite grain structures such as, uniform distribution of coarse- and very fine-ferrite grains, and bimodal distribution of ferrite grain sizes comprising of coarse grains (~12 μm) and very fine grains (<2 μm). Very fine-grained dual-phase structure offered the best combination of tensile-strength and ductility among all the samples. The above microstructures have been compared in terms of their strain-hardening rate and the mechanism of plastic deformation.