Abstract:Isothermal compression tests of NiPt15 alloys at temperatures ranging from 950 to 1150℃ and strain rates from 0.01 to 3s-1 were performed on Gleeble-3500 thermo-simulation machine. Based on stress-strain relationship curve of NiPt15 and hot processing maps during the hot deformation process were established. The power dissipation situation of NiPt15 alloy at different stage were analyzed. The damage instability mechanism of NiPt15 alloy was elucidated. According to the dynamic material model presented by Prasad, hot processing maps for hot working condition were established based on the effect of power dissipation and instability coefficient associated with various kinds of temperatures and stain rates. The results showed that the deformation temperature is the main factor affection of the curve variation trend and dynamic recrystallization. Moreover, the higher of deformation temperature and the lower of deformation rate, the dynamic recrystallization will be the more sufficient. Subsequently, the instability mechanism of NiPt15 alloy in thermal processing mainly included local plastic deformation, shear deformation zone and cracking. With the increase of true strain, local plastic deformation occured firstly, then shear deformation zone replaced it, and finally it evolved into cracking. The excellent safe processing zone for NiPt15 alloy were mainly concentrated in the non-instability zone . That was to say, the deformation parameters were within the range of 1000~1100℃, 0.03~0.1s-1 and 1100~1130℃, 0.01~0.03s-1. Moreover, the thermal processing map was verified by microstructure analysis.