Gradient ultrafine ferrite and martensite structure and its tensile properties by asymmetric rolling in low carbon microalloyed steel

摘要

Asymmetric rolling (AsR) was carried out to achieve a gradient ultrafine ferrite and martensite duplex structure in a commercial low-carbon microalloyed steel and compared with symmetric rolling. Two specific fiber textures <110>//RD and <111>//ND were developed through the thickness when imposing shear strains by AsR. In hibition of plastic instability in the ultrafine ferrite was closely associated with the gradient grain-size distribution, beneficial shear fiber textures and the dispersed martensite, resulting in high strength (～905 MPa) with good ductility (～17%).