A study on ultrahigh strength steel plate subjected to novel thermo-mechanical control process was presented. The mechanical properties examination showed that the investigated steel exhibited excellent combination of...A study on ultrahigh strength steel plate subjected to novel thermo-mechanical control process was presented. The mechanical properties examination showed that the investigated steel exhibited excellent combination of ultra-high strength（ 2 200 MPa） and toughness（ 26 J）. The microstructure of the experimental steel was observed by scanning electron microscope and transmission electron microscope. Desired martensitic lath with width of about 180- 250 nm was obtained. Nanostructured carbide precipitates with sizes of 20-50 nm,which contained Nb,Ti and Mo,were observed in the lath martensitic microstructure,and confirmed to be MC-type carbides with B1 structure by means of selected area electron diffraction.The compositional characteristics revealed by energy dispersive X-ray spectrometer mapping implied that the carbide forming elements Nb,Ti and Mo distributed in the precipitates evenly. Three-dimensional atom probe tomography reconstruction further indicated that Mo incorporated into the precipitates without enrichment in the carbide-matrix interface and probably substituted for Nb and Ti to form the（ Nb,Ti,Mo） C carbides.展开更多
基金Item Sponsored by High Technology Research and Development Program of China(2012AA03A508)
文摘A study on ultrahigh strength steel plate subjected to novel thermo-mechanical control process was presented. The mechanical properties examination showed that the investigated steel exhibited excellent combination of ultra-high strength（ 2 200 MPa） and toughness（ 26 J）. The microstructure of the experimental steel was observed by scanning electron microscope and transmission electron microscope. Desired martensitic lath with width of about 180- 250 nm was obtained. Nanostructured carbide precipitates with sizes of 20-50 nm,which contained Nb,Ti and Mo,were observed in the lath martensitic microstructure,and confirmed to be MC-type carbides with B1 structure by means of selected area electron diffraction.The compositional characteristics revealed by energy dispersive X-ray spectrometer mapping implied that the carbide forming elements Nb,Ti and Mo distributed in the precipitates evenly. Three-dimensional atom probe tomography reconstruction further indicated that Mo incorporated into the precipitates without enrichment in the carbide-matrix interface and probably substituted for Nb and Ti to form the（ Nb,Ti,Mo） C carbides.
