Thermal Deformation Behavior and Microstructure Evolution of Cu−3.27Ti Alloy

The hot compression simulation test of Cu−3.27Ti alloy as cast was carried out at deformation temperature of 750−900 ℃ and strain rate of 0.1−10.0 s⁻¹ with Gleeble−3500 thermal simulation testing machine. On this basis, the high temperature constitutive relation model of Cu−3.27Ti alloy was established and the hot working diagram was drawn. The effects of thermal deformation temperature and strain rate on the thermal deformation behavior and microstructure evolution of Cu−3.27Ti alloy were studied, and the technological parameters of thermal deformation were optimized. The results show that the established high temperature constitutive relation model can well characterize the relationship between deformation temperature, strain rate and flow stress of Cu−3.27Ti alloy. The hot working diagram shows that there is one peak power dissipation region and two rheological instability regions in Cu−3.27Ti alloy, the peak power dissipation is about 0.27, the corresponding deformation condition is 900 ℃, and the peak power dissipation region does not overlap with the instability region. Theoretically, Cu−3.27Ti alloy has better thermal workability at 900 ℃. Deformation temperature and strain rate have obvious effects on the dynamic recrystallization ratio and average diameter of recrystallization grains of Cu−3.27Ti alloy microstructure. The dynamic recrystallization ratio and average diameter of recrystallization grains increase with the increase of deformation temperature and strain rate, and the influence of deformation temperature and strain rate on the average diameter of grain becomes more significant when the microstructure is completely recrystallized. When Cu−3.27Ti alloy is deformed at 750 ℃, the fine recrystallized grains are distributed around the initial grains in chain structure, showing rheological instability characteristics. When the deformation condition is 900 ℃/10.0 s⁻¹, the microstructure of the alloy has been completely recrystallized and the grains are relatively small and uniform, which is suitable for hot processing.