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 hot deformation behavior of pure nickel with coarse, columnar grains in the temperature range of 950-1150 ℃ at intervals of 50℃ and in the strain rate range of 0.001-10.000 s^-1 at intervals of one order of magn...The hot deformation behavior of pure nickel with coarse, columnar grains in the temperature range of 950-1150 ℃ at intervals of 50℃ and in the strain rate range of 0.001-10.000 s^-1 at intervals of one order of magnitude was investigated by isothermal hot compressive testing with the compression ratio of 70%. The results reveal that the strain rate and the temperature strongly affect the flow stress during hot deformation and that flow stress increases with the increase in strain rate while decreases with temperature increasing. Moreover, the relationship among flow stress, strain rate and temperature can be represented by the Zener-Hollomon parameter with the calculated apparent activation energy of 312.403 kJ·mol^-1, and the variation of activation energy is sensitive to strain rate rather than temperature. In addition, the dynamic recrystallization (DRX) analysis reveals that the DRX behavior of nickel is evidently affected by both deformation temperature and strain rate and that the distinct mechanisms of nucleation are the bulging of serrated grain boundaries and the development of twinning.展开更多
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financially supported by the National Natural Science Foundation of China (Nos. 51271076 and 51474101)
文摘The hot deformation behavior of pure nickel with coarse, columnar grains in the temperature range of 950-1150 ℃ at intervals of 50℃ and in the strain rate range of 0.001-10.000 s^-1 at intervals of one order of magnitude was investigated by isothermal hot compressive testing with the compression ratio of 70%. The results reveal that the strain rate and the temperature strongly affect the flow stress during hot deformation and that flow stress increases with the increase in strain rate while decreases with temperature increasing. Moreover, the relationship among flow stress, strain rate and temperature can be represented by the Zener-Hollomon parameter with the calculated apparent activation energy of 312.403 kJ·mol^-1, and the variation of activation energy is sensitive to strain rate rather than temperature. In addition, the dynamic recrystallization (DRX) analysis reveals that the DRX behavior of nickel is evidently affected by both deformation temperature and strain rate and that the distinct mechanisms of nucleation are the bulging of serrated grain boundaries and the development of twinning.
