Hot compressive deformation and microstructural evolution of 60NiTi alloy

Abstract

Hot deformation behavior and microstructure of 60NiTi alloy during hot compressive deformation were investigated using Gleeble−3500 thermal simulation test machine in the temperature range of 500−650 °C and strain rate range of 0.001−1 s−1. The constitutive equation of hot compression was constructed and the hot processing maps were plotted. When the compression temperature rose or the strain rate declined, the peak stress reduced. The hot deformation activation energy was calculated as 327.89 kJ/mol, and the proper hot working parameters of compression temperature of 600−650 °C and strain rate of 0.005−0.05 s−1 were obtained. The recrystallization degree increased with increasing compression temperature. When the strain rate increased, both dislocation density and number of twins were improved, and the Ni3Ti phase tended to aggregate. Ni3Ti precipitation phase was beneficial to inducing dynamic recrystallization of the 60NiTi alloy. The dynamic recovery, dynamic recrystallization and twinning took place during hot compressive deformation of the 60NiTi alloy.