The mechanical alloying effects on the structures of Fe71.3Al28.4(CeO2)(0.3) and Fe73.3Al9.8-Si-16.6(CeO2)(0.3) samples have been investigated mainly by Mossbauer spectroscopy and X-ray diffraction. it is found that w...The mechanical alloying effects on the structures of Fe71.3Al28.4(CeO2)(0.3) and Fe73.3Al9.8-Si-16.6(CeO2)(0.3) samples have been investigated mainly by Mossbauer spectroscopy and X-ray diffraction. it is found that with the increase of milling time, a substituting disordered alpha-Fe solution is formed gradually and almost completed after milled for 72 h. Further increasing milling time causes the atomic rearrangement within the powders. Correspondingly, the average lattice parameter and average crystalline size change until 72 h and remain constant after 72 h. The addition of Si leads to the higher disordered degree reflected in the smaller average hyperfine field and larger mean square deviation.展开更多
Non-dimensionalized equations and boundary conditions are presented for the torsion problem of an anisotropic body. The error of the fundamental solution cited in some boundary element books Is pointed out after an ex...Non-dimensionalized equations and boundary conditions are presented for the torsion problem of an anisotropic body. The error of the fundamental solution cited in some boundary element books Is pointed out after an examination of the fundamental solution. Furthermore,a necessary and sufficient boundary integral equation is given for the problem and compared with the conventional boundary integral equation. Numerical results show that great errors of the boundary shear stresses obtained by the conventional boundary integral equation appear with a small error of torsion stiffness. Meanwhile,the necessary and sufficient;boundary integral equation always gives accurate results.展开更多
interfacial geometric morphology, chemistry and microstructure have been studied by SEM, EDAX, HREM, and XPS. It is found that the oxide scale/metal interface consists of two layers. The first one is amorphous SiO2 gr...interfacial geometric morphology, chemistry and microstructure have been studied by SEM, EDAX, HREM, and XPS. It is found that the oxide scale/metal interface consists of two layers. The first one is amorphous SiO2 growing inward metal matrix, and the second one under the first layer is TiO2 distributing in metal matrix. There is microstructural transition zone at Cr2O3/SiO2 interface, and an atomic mixed zone with 8 nm width at SiO2/metal interface. The transition zone which is saturated with Cr diffusing from oxide scale exists at the oxide scale/glass interface. The reasons why sand-blasting process can improve bonding strength of the oxide scale and the metal are also discussed. The ideal interfaces are proposed finally.展开更多
文摘The mechanical alloying effects on the structures of Fe71.3Al28.4(CeO2)(0.3) and Fe73.3Al9.8-Si-16.6(CeO2)(0.3) samples have been investigated mainly by Mossbauer spectroscopy and X-ray diffraction. it is found that with the increase of milling time, a substituting disordered alpha-Fe solution is formed gradually and almost completed after milled for 72 h. Further increasing milling time causes the atomic rearrangement within the powders. Correspondingly, the average lattice parameter and average crystalline size change until 72 h and remain constant after 72 h. The addition of Si leads to the higher disordered degree reflected in the smaller average hyperfine field and larger mean square deviation.
文摘Non-dimensionalized equations and boundary conditions are presented for the torsion problem of an anisotropic body. The error of the fundamental solution cited in some boundary element books Is pointed out after an examination of the fundamental solution. Furthermore,a necessary and sufficient boundary integral equation is given for the problem and compared with the conventional boundary integral equation. Numerical results show that great errors of the boundary shear stresses obtained by the conventional boundary integral equation appear with a small error of torsion stiffness. Meanwhile,the necessary and sufficient;boundary integral equation always gives accurate results.
文摘interfacial geometric morphology, chemistry and microstructure have been studied by SEM, EDAX, HREM, and XPS. It is found that the oxide scale/metal interface consists of two layers. The first one is amorphous SiO2 growing inward metal matrix, and the second one under the first layer is TiO2 distributing in metal matrix. There is microstructural transition zone at Cr2O3/SiO2 interface, and an atomic mixed zone with 8 nm width at SiO2/metal interface. The transition zone which is saturated with Cr diffusing from oxide scale exists at the oxide scale/glass interface. The reasons why sand-blasting process can improve bonding strength of the oxide scale and the metal are also discussed. The ideal interfaces are proposed finally.
