Abstract
In this paper, we demonstrate the design and manufacture of super-high strength medium Mn steel with good ductility, via the combination of warm rolling and V alloying. This new strategy produced not only the extensive precipitation of fine VC particles in both ferrite and austenite but also the bimodal size distribution of retained austenite (RA) grains. A substantial increase of yield strength up to 650 MPa was achieved after the intercritical annealing (IA) of this V-alloyed medium Mn steel without deteriorating ductility; whereas the calculated precipitation strengthening using the classical Ashby-Orowan theory is no more than 400 MPa. Quantifying possible strengthening mechanisms revealed that dislocation strengthening should make an additional contribution because recovery in austenite could be strongly retarded by the nanosized precipitates. In this V-alloyed steel, the coarse RA grains firstly transformed to martensite during yielding at the much higher stress threshold, followed by a significant work hardening during successive deformation due to dislocations multiplication, twinning-induced-plasticity (TWIP) and transformation-induced-plasticity (TRIP) in fine RA grains. The best achieved combination of tensile properties included 1.8 GPa ultimate tensile strength, 1.0 GPa yield strength and 18% total elongation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
