The flow behavior of already forged Ti-46.2Al-2.5V-1.0Cr-0.3Ni alloy was investigated by the isothermal compression experiments. The direction of secondary hot deformation was taken to be vertical to the former forgin...The flow behavior of already forged Ti-46.2Al-2.5V-1.0Cr-0.3Ni alloy was investigated by the isothermal compression experiments. The direction of secondary hot deformation was taken to be vertical to the former forging axis. And the deformation activation energy was calculated. Specimens have three kinds of starting microstructures, i.e. as-forged, relief annealed and duplex. The true strain—stress curves show that the duplex microstructure has the lowest flow resistance, better steady-state flow behavior compared with other two microstructures. It is found that obtaining duplex microstructure makes the work hardening rate and the strain rate sensitivity increase. The duplex microstructure alloy has the lowest value.展开更多
The electron structure ofγ/α2 phase boundaries in lamellar colonies in Ti-47Al-2M(M=Nb, Cr, V) (mole fraction, %) alloys was theoretically investigated by Empirical Electron Theory of Solid and Molecules (EET) and t...The electron structure ofγ/α2 phase boundaries in lamellar colonies in Ti-47Al-2M(M=Nb, Cr, V) (mole fraction, %) alloys was theoretically investigated by Empirical Electron Theory of Solid and Molecules (EET) and the bond-length-difference (BLD) method. Average-Atom-Model was employed to calculate valence electron structure of TiAl intermetallics containing site substitution elements. On this basis, the boundary condition of electron movement was employed in the improved Thomas-Fermi-Dirac (TFD) theory to decide the continuity of the electron density of the lamellar colonies interface and it is found that ofγ/α2 interface is continuous(Δρ<10%). Furthermore, it is found that adding alloying elements (including Nb, Cr, and V) can improve the electron density (ρ) ofγ/α2 interfaces, and decrease the electron density difference(Δρ)ofγ/α2 interfaces. Adding V element decreasingΔρis more remarkable than other site substitution elements. According to electron structure study ofγ/α2 interfaces in Ti-47Al-2M alloys, the added elements improve mechanical properties of the alloy in the following order: V>Cr>Nb.展开更多
基金Project(51201147)supported by the National Natural Science Foundation of ChinaProject(14JJ6016)supported by the Natural Science Foundation of Hunan Province,ChinaProject(INFO-115-B01)supported by the Informalization Construction Project of Chinese Academy of Sciences,China
基金Project(2002AA305209) supported by the High Tech Research and Development Program of China
文摘The flow behavior of already forged Ti-46.2Al-2.5V-1.0Cr-0.3Ni alloy was investigated by the isothermal compression experiments. The direction of secondary hot deformation was taken to be vertical to the former forging axis. And the deformation activation energy was calculated. Specimens have three kinds of starting microstructures, i.e. as-forged, relief annealed and duplex. The true strain—stress curves show that the duplex microstructure has the lowest flow resistance, better steady-state flow behavior compared with other two microstructures. It is found that obtaining duplex microstructure makes the work hardening rate and the strain rate sensitivity increase. The duplex microstructure alloy has the lowest value.
基金Project(50674037) supported by the National Natural Science Foundation of China
文摘The electron structure ofγ/α2 phase boundaries in lamellar colonies in Ti-47Al-2M(M=Nb, Cr, V) (mole fraction, %) alloys was theoretically investigated by Empirical Electron Theory of Solid and Molecules (EET) and the bond-length-difference (BLD) method. Average-Atom-Model was employed to calculate valence electron structure of TiAl intermetallics containing site substitution elements. On this basis, the boundary condition of electron movement was employed in the improved Thomas-Fermi-Dirac (TFD) theory to decide the continuity of the electron density of the lamellar colonies interface and it is found that ofγ/α2 interface is continuous(Δρ<10%). Furthermore, it is found that adding alloying elements (including Nb, Cr, and V) can improve the electron density (ρ) ofγ/α2 interfaces, and decrease the electron density difference(Δρ)ofγ/α2 interfaces. Adding V element decreasingΔρis more remarkable than other site substitution elements. According to electron structure study ofγ/α2 interfaces in Ti-47Al-2M alloys, the added elements improve mechanical properties of the alloy in the following order: V>Cr>Nb.
