Yield Strength Enhancement Without Ductility Loss Through Controlling the Intercritical Annealing Time in Medium‐Mn Steels

Herein, the effect of shortening intercritical annealing (IA) time in a two-step process “intercritical and tempering (IAT)” on microstructure mechanical properties medium-manganese steel (MMnS) made Fe–0.05C–7Mn–1.5Cu–1.5Ni–1.5Al–1.5Si–0.5Mo (wt%) containing copper-rich (CRP) Ni(Al/Mn) precipitates is investigated. The atom probe tomography (APT), electron backscattering diffraction (EBSD), synchrotron X-ray (SYXRD) are used to study precipitation, phase evolution, austenite stability, deformation mechanisms. Shortening IA step, which carried out at 700 °C, from 2 min (IAT-2) 1 (IAT-1), results yield strength (YS) increment around 218 MPa with less than 1% loss ductility. While enhanced IAT-1 attributed four times higher precipitates’ number density (n), insignificant ductility stability factor 4.5 9.2 IAT-2 IAT-1, respectively. simultaneous increase YS without reflects that controlling promising strategy overcome trade-off need for additions costly alloying elements such as Ni, Al, Mn, Cu.