The high temperature tensile deformation and fracture behaviors of Ni- based superalloy K403 were studied using Gleeble-1500 thermo-simulation machine at the temperatures of 850 to 1 000 ℃ and strain rates of 0.01 to 10 s- 1. The optical microscope(OM),scanning electron microscope(SEM)and transmission electron microscope(TEM)were employed to analyze the microstructure evolution of tensile deformation and fracture mechanism at high temperatures. The results show that with the increase of the strain rates,the...