To investigate the temperature distribution and solidification shell profile in a continuous casting process for round bars, transient mathematical models have been developed to describe the thermal process. Then Fini...To investigate the temperature distribution and solidification shell profile in a continuous casting process for round bars, transient mathematical models have been developed to describe the thermal process. Then Finite Element Method (FEM) has been applied to simulate the solidification process. Parameters including casting speed, casting temperature and cooling conditions have been analyzed. It is shown that different parameters have different influence on the thermal process and must be carefully controlled in continuous casting process. Finally, the simulated results are compared with the experimental ones.展开更多
The superiorities of air-cooled bainitic steels were described. A series of air-cooled bainitic steels containing manganese were developed and presented, which include low carbon granular bainitic steels, low carbon g...The superiorities of air-cooled bainitic steels were described. A series of air-cooled bainitic steels containing manganese were developed and presented, which include low carbon granular bainitic steels, low carbon grain-boundary allotriomorphic ferrite/granular bainite dual phase steels, medium and medium high carbon bainite/martensite dual phase steel, low carbon carbide free bainite/martensite dual phase steels and casting bainitic steels. The development of ultra-low carbon bainitic steels in China was also introduced.展开更多
A high activity and large capacity of hydrogen storage alloy Mg2Ni by hydriding combustion synthesis was investigated by means of pressure composition isotherms, X-ray diffraction and scanning electron microscopy. The...A high activity and large capacity of hydrogen storage alloy Mg2Ni by hydriding combustion synthesis was investigated by means of pressure composition isotherms, X-ray diffraction and scanning electron microscopy. The results showed that the maximum hydrogen absorption capacity of Mg2Ni is 3.25 mass fraction at 523 K, just after synthesis without any activation. The relationships between the equilibrium plateau pressure and the temperature for Mg2Ni were lgp (0.1 MPa)=-3026/T+5.814 (523 K≤T≤623 K) for hydriding and Igp (0.1 MPa)=-3613/T+6.715 (523 K≤T ≤623 K) for dehydriding. The kinetic equation is [-ln(1-a)]3/2 = kt and the apparent activation energy for the nucleation and growth-controlled hydrogen absorption and desorption were determined to be 64.3±2.31kJ/(mol.H2) and 59.9±2.99kJ/(mol.H2)respectively.展开更多
The research and development of RE magnets in China were briefly reviewed. The research achievements of RE magnets reach international level. The intermetallic nitrides with ThMn12-type structure of RFe series which p...The research and development of RE magnets in China were briefly reviewed. The research achievements of RE magnets reach international level. The intermetallic nitrides with ThMn12-type structure of RFe series which possess Chinese proprietary were prepared. The output of RE magnets has ranked second in the world. The production of RE magnets will be steadily expanding with the expiration of NdFeB patent in 2003. Some related data were also presented.展开更多
The oxidation rate of a high temperature titanium alloy in air at 650℃ could be decreased significantly by means of ion implantation of 3×10 16 and 3×10 17 ions/cm 2 Nb. The microstructure and al...The oxidation rate of a high temperature titanium alloy in air at 650℃ could be decreased significantly by means of ion implantation of 3×10 16 and 3×10 17 ions/cm 2 Nb. The microstructure and alloy elements distribution in the oxidation scale of unimplanted and Nb implanted titanium alloy were investigated by using SEM, XRD and AES. The addition of Nb could reduce the number of point defects and decrease the solubility of oxygen in the alloy substrate. Therefore, the oxidation resistance of the alloy in air at 650℃ is remarkably improved.展开更多
his study focused on the oxidation behavior of the ultra high strength metastable β 21S Titanium alloy (Ti 15Mo 2.7Nb 3Al 0.2Si, wt%) over the temperature range 600～800℃. The experimental results show that t...his study focused on the oxidation behavior of the ultra high strength metastable β 21S Titanium alloy (Ti 15Mo 2.7Nb 3Al 0.2Si, wt%) over the temperature range 600～800℃. The experimental results show that the β 21S alloy has a better oxidation resistance than the commercial pure titanium, oxidation proceeds by growth of a surface oxide of TiO 2 and oxygen dissolution into the metal, oxidation initially follows an approximate linear oxidation rate which is followed by an approximate parabolic rate, the activation energies are 24.0 kJ/mol and 47.6 kJ/mol, respectively.展开更多
文摘To investigate the temperature distribution and solidification shell profile in a continuous casting process for round bars, transient mathematical models have been developed to describe the thermal process. Then Finite Element Method (FEM) has been applied to simulate the solidification process. Parameters including casting speed, casting temperature and cooling conditions have been analyzed. It is shown that different parameters have different influence on the thermal process and must be carefully controlled in continuous casting process. Finally, the simulated results are compared with the experimental ones.
文摘The superiorities of air-cooled bainitic steels were described. A series of air-cooled bainitic steels containing manganese were developed and presented, which include low carbon granular bainitic steels, low carbon grain-boundary allotriomorphic ferrite/granular bainite dual phase steels, medium and medium high carbon bainite/martensite dual phase steel, low carbon carbide free bainite/martensite dual phase steels and casting bainitic steels. The development of ultra-low carbon bainitic steels in China was also introduced.
文摘A high activity and large capacity of hydrogen storage alloy Mg2Ni by hydriding combustion synthesis was investigated by means of pressure composition isotherms, X-ray diffraction and scanning electron microscopy. The results showed that the maximum hydrogen absorption capacity of Mg2Ni is 3.25 mass fraction at 523 K, just after synthesis without any activation. The relationships between the equilibrium plateau pressure and the temperature for Mg2Ni were lgp (0.1 MPa)=-3026/T+5.814 (523 K≤T≤623 K) for hydriding and Igp (0.1 MPa)=-3613/T+6.715 (523 K≤T ≤623 K) for dehydriding. The kinetic equation is [-ln(1-a)]3/2 = kt and the apparent activation energy for the nucleation and growth-controlled hydrogen absorption and desorption were determined to be 64.3±2.31kJ/(mol.H2) and 59.9±2.99kJ/(mol.H2)respectively.
文摘The research and development of RE magnets in China were briefly reviewed. The research achievements of RE magnets reach international level. The intermetallic nitrides with ThMn12-type structure of RFe series which possess Chinese proprietary were prepared. The output of RE magnets has ranked second in the world. The production of RE magnets will be steadily expanding with the expiration of NdFeB patent in 2003. Some related data were also presented.
文摘The oxidation rate of a high temperature titanium alloy in air at 650℃ could be decreased significantly by means of ion implantation of 3×10 16 and 3×10 17 ions/cm 2 Nb. The microstructure and alloy elements distribution in the oxidation scale of unimplanted and Nb implanted titanium alloy were investigated by using SEM, XRD and AES. The addition of Nb could reduce the number of point defects and decrease the solubility of oxygen in the alloy substrate. Therefore, the oxidation resistance of the alloy in air at 650℃ is remarkably improved.
文摘his study focused on the oxidation behavior of the ultra high strength metastable β 21S Titanium alloy (Ti 15Mo 2.7Nb 3Al 0.2Si, wt%) over the temperature range 600～800℃. The experimental results show that the β 21S alloy has a better oxidation resistance than the commercial pure titanium, oxidation proceeds by growth of a surface oxide of TiO 2 and oxygen dissolution into the metal, oxidation initially follows an approximate linear oxidation rate which is followed by an approximate parabolic rate, the activation energies are 24.0 kJ/mol and 47.6 kJ/mol, respectively.
