554-566The dynamic mechanical properties of GH4720Li nickel base superalloy under high and low strain rates in a wide
temperature range have been studied, and a constitutive model with higher fitting progress have been established. The
experimental results show that the abnormal phenomenon of dynamic mechanical properties of GH4720Li alloy appears
under the condition of high strain rate. This is because the change of Cr (MO) content in precipitates and the change of
precipitate morphology lead to the difference of dynamic mechanical properties of GH4720Li alloy at high and low strain
rates. Besides, A new piecewise function model based on a phenomenological representation of the stress-strain curves is
proposed to describe the constitutive equation of Nickel-based superalloy GH4720Li of stress-strain curves. Meanwhile,
new methods to obtain the material constant k and C are proposed to predicted accurately the flow stress. The comparison
between calculated values and experimental values based on the new constitutive modeling shows that these methods for
obtaining material constants k and C are valid and the new function model is significant for establishing constitutive
equations of Nickel-based superalloy GH4720Li in hot deformation processes
