A three-step cooling pattern on the runout table（ROT）was conducted for the hot rolled TRIP steel.Microstructural evolution during thermomechanical controlled processing（TMCP）was investigated.Processing condition o...A three-step cooling pattern on the runout table（ROT）was conducted for the hot rolled TRIP steel.Microstructural evolution during thermomechanical controlled processing（TMCP）was investigated.Processing condition of controlled cooling on a ROT in the laboratory rolling mill was discussed.The results indicated that the microstructure containing polygonal ferrite,granular bainite and a significant amount of the stable retained austenite can be obtained through three-step cooling on the ROT after hot rolling.TMCP led to ferrite grain refinement.Controlled cooling after hot rolling resulted in the stability of the remaining austenite and a satisfactory TRIP effect.Excellent mechanical properties were obtained through TMCP for the hot rolled TRIP steel.展开更多
The effect of thermomechanical processing（TMP）on the mechanical properties of hot rolled multiphase steel was investigated.TMP was conducted using a laboratory hot rolling mill,in which three different kinds of fini...The effect of thermomechanical processing（TMP）on the mechanical properties of hot rolled multiphase steel was investigated.TMP was conducted using a laboratory hot rolling mill,in which three different kinds of finish rolling deformation degrees and temperatures were applied.The results indicate that polygonal ferrite,granular bainite,and a considerable amount of stabilized retained austenite can be obtained by TMP.The stability of the retained austenite increases with decreasing finish rolling temperature and increasing finish rolling deformation degrees.Ultimate tensile strength（σb）,total elongation（δ）,and the product of ultimate tensile strength by total elongation（σb·δ）for 50% reduction at finish rolling temperature of 700 ℃ reach maximum values [791 MPa,36% and 28 476（MPa·%）,respectively].展开更多
Laser molecular beam epitaxy(laser MBE)technique was utilized to grow the barium titanate(BaTiO_(3),BTO)thin films on SrTiO_(3)(100)substrates.The surface morphology of the BaTiO_(3) thin films was studied by atomic f...Laser molecular beam epitaxy(laser MBE)technique was utilized to grow the barium titanate(BaTiO_(3),BTO)thin films on SrTiO_(3)(100)substrates.The surface morphology of the BaTiO_(3) thin films was studied by atomic force microscopy(AFM).Two-and three-dimensional AFM images were obtained.The root mean square surface roughness,the height profile,the histogram and the bearing ratio of the height distributions for the BaTiO_(3) thin films were analyzed in detail.The results indicate that the laser MBE thin films exhibit an atomically smooth surface.展开更多
A new model, which involves viscous and multi-phase effects, was given to study cavitating flows. A local compressible model was established by introducing a density-pressure function to account for the two-phase flow...A new model, which involves viscous and multi-phase effects, was given to study cavitating flows. A local compressible model was established by introducing a density-pressure function to account for the two-phase flow of water/vapor and the transition from one phase to the other. An algorithm for calculating variable-density N-S equations of cavitating flow problem was put forward. The present method yields reasonable results for both steady and unsteady cavitating flows in 2D and 3D cases. The numerical results of unsteady character of cavitating flows around hydrofoils coincide well with experimental data. It indicates the feasibility to apply this method to a variety of cavitating flows of practical problems.展开更多
基金Item Sponsored by National Natural Science Foundation of China(50334010)
文摘A three-step cooling pattern on the runout table（ROT）was conducted for the hot rolled TRIP steel.Microstructural evolution during thermomechanical controlled processing（TMCP）was investigated.Processing condition of controlled cooling on a ROT in the laboratory rolling mill was discussed.The results indicated that the microstructure containing polygonal ferrite,granular bainite and a significant amount of the stable retained austenite can be obtained through three-step cooling on the ROT after hot rolling.TMCP led to ferrite grain refinement.Controlled cooling after hot rolling resulted in the stability of the remaining austenite and a satisfactory TRIP effect.Excellent mechanical properties were obtained through TMCP for the hot rolled TRIP steel.
基金Item Sponsored by National Natural Science Foundation of China(50334010)
文摘The effect of thermomechanical processing（TMP）on the mechanical properties of hot rolled multiphase steel was investigated.TMP was conducted using a laboratory hot rolling mill,in which three different kinds of finish rolling deformation degrees and temperatures were applied.The results indicate that polygonal ferrite,granular bainite,and a considerable amount of stabilized retained austenite can be obtained by TMP.The stability of the retained austenite increases with decreasing finish rolling temperature and increasing finish rolling deformation degrees.Ultimate tensile strength（σb）,total elongation（δ）,and the product of ultimate tensile strength by total elongation（σb·δ）for 50% reduction at finish rolling temperature of 700 ℃ reach maximum values [791 MPa,36% and 28 476（MPa·%）,respectively].
基金Supported by the National Natural Science Foundation of China under Grant Nos.59392800 and 69437101the Chinese Academy of Sciences,the National Superconducting Research Center,and the Research Grant No.94-189 RG/PHYS/AS of the Third World Academy of Sciences.
文摘Laser molecular beam epitaxy(laser MBE)technique was utilized to grow the barium titanate(BaTiO_(3),BTO)thin films on SrTiO_(3)(100)substrates.The surface morphology of the BaTiO_(3) thin films was studied by atomic force microscopy(AFM).Two-and three-dimensional AFM images were obtained.The root mean square surface roughness,the height profile,the histogram and the bearing ratio of the height distributions for the BaTiO_(3) thin films were analyzed in detail.The results indicate that the laser MBE thin films exhibit an atomically smooth surface.
文摘A new model, which involves viscous and multi-phase effects, was given to study cavitating flows. A local compressible model was established by introducing a density-pressure function to account for the two-phase flow of water/vapor and the transition from one phase to the other. An algorithm for calculating variable-density N-S equations of cavitating flow problem was put forward. The present method yields reasonable results for both steady and unsteady cavitating flows in 2D and 3D cases. The numerical results of unsteady character of cavitating flows around hydrofoils coincide well with experimental data. It indicates the feasibility to apply this method to a variety of cavitating flows of practical problems.
