Hot Deformation Behavior and Constitutive Models of Ti600 Alloy in (α plus β) Phase Region

The high-temperature deformation behavior of Ti600 alloy with a lamellar initial microstructure was investigated in the temperature range of 800 similar to 960 C and the strain rate range of 10(-3) similar to 1 s(-1). Subsequently, the strain hardening exponent (n) was proposed to characterize the competition of flow softening and work hardening. The softening behavior of this alloy was also studied according to flow curve analysis and microstructure observation. The results indicate that deformation parameters have significant influences on the flow behavior of Ti600 alloy. The n-value gradually decreases after the peak strain, which indicates that the dynamic softening begins to take dominant. The dynamic softening behavior of Ti600 alloy mainly attributes to the bending, fragmentation, dynamic recovery and recrystallization of alpha phase during the high-temperature deformation according to the microstructure characterization. Based on experimental data, original strain-compensated Arrhenius, Hensel-Spittel and modified Arrhenius constitutive models are established to describe the deformation behavior of Ti600 alloy. The flow stresses predicted by three models are compared with experimental results, and the calculated correlation coefficients are 0.965, 0.989, and 0.997. Also, the values of average absolute relative error are 12.86%, 9.74%, and 3.26%. These results suggest that three models can descript the flow behavior of Ti600 alloy, and the modified Arrhenius model exhibits the highest prediction accuracy.