Microstructure Evolution of Ultrafine Ferrite/Martensitic Dual Phase Steel in Two-stage Rolling Deformation and Aging State
Two-stage rolling deformation and aging treatment were carried out for the copper-containing low-alloy high-strength steel,which formed an ultra-fine-grained ferrite/martensite dual-phase structure.Scanning electron microscopy and electron backscatter diffraction were used to analyze the microstructure evolution of dual-phase steel under different processes.Combined with mechanical properties testing,the mechanism of synergistic strengthening and toughening of fine crystal strengthening and nanophase precipitation was discussed.The results show that after the above-mentioned deformation and aging treatment,the obtained ultrafine-grained ferrite/martensitic dual-phase steel has a good strength-plasticity combination,and the average grain size is 1.23 μm.With the prolonging of aging time,the fine second phase is dispersively precipitated and evenly distributed,which increases the yield strength of the experimental steel.
two-stage rolling deformationdual-phase steelultrafine grainprecipitates
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