Effect of equal channel angular pressing on microstructure and mechanical properties of IF steel

The microstructural evolution and the variation of the mechanical properties of interstitial free (IF) steel were analyzed after different equal channel angular pressing (ECAP) histories. The bcc ferrite structure in the annealed specimens was characterized by an average grain size of 250 μm without any preferred orientation. A comparison of the transmission electron microscopy (TEM) evidence shows that Route A is more efficient than Route C with regard to both the rate with which a grain structure emerges and the amount of grain refinement obtained. A high tensile strength above 800 MPa and a tensile elongation over 155 achieved with both ECAP routes was regarded as a good combination of strength and ductility.