چكيده به لاتين
Abstract:
Hot deformation behavior of X-750 superalloy was investigated using the hot compression test in the temperature range of 1000–1100 °C, and strain rate of 0.001–1 s-1. The experimental results showed that the flow stress of superalloy has been significantly sensitive to the strain, the strain rate and the deformation temperature. The flow stress decreases with increasing of deformation temperature and decreasing of strain rate. Meanwhile, the flow stress increased quickly with increasing the strain, and then decreased to a steady state.
Processing maps for hot working are developed on the basis of the variations of efficiency of power dissipation with temperature and strain rate. Hot deformation equation is given to characterize the dependence of peak stress on the temperature and strain rate. and hot deformation apparent activation energy of the Ni-base superalloy is about 460 kJ/mol. The power dissipation map reveals that a domain of dynamic recrystallization (DRX) exists in the temperature range of 1000–1100 °C and strain rate range of 0.01–0.001 s-1, with its peak efficiency of 40% at about 1100 °C and 0.01 s-1, which are the optimum hot working parameters. Analysis of the flow behavior and microstructure observations indicated that dynamic recrystallization occurred at higher temperatures and lower strain rates.
Keywords: Superalloy, Hot Deformation, Processing Map, DRX, Flow Instability
