| Abstract: | Two kinds of C-Si-Mn-Cr series tested steels were designed to obtain dual phase microstructures of ferrite(F)+martensite(M)or ferrite(F)+bainite(B)with different mechanical properties.Effects of strengthening phase on yielding and fracture behaviours during uniaxial tension of dual phase steel were discussed.Compared with hot-rolled martensite dual phase steel,ferrite-bainite dual phase steel has high ratio of yield strength to tensile strength(YS/TS)and low elongation.During necking process of uniaxial tension,microvoids of ferrite-martensite steel are generated by fracture of ferrite/martensite boundary or martensite islands with irregular shape.But ferrite matrix elongated remarkably along deformation direction,and strengthening phase also coordinated with ferrite matrix.Compatible deformation between ferrite and bainite is distinct.Ferrite-bainite dual phase steel has fine and less microvoid,and phase boundary of ferrite and bainite is beneficial for restraining generation and extending of microvoid. |
