Multi-angle Study on the Hot Deformation Characteristics of Ti-55 Alloy
摘要
High-temperature tensile tests were conducted on Ti-55 alloy under varying conditions to investigate its deformation characteristics at elevated temperatures. Results indicated a higher tendency for superplastic deformation at a high temperature of 950 °C and a low strain rate of 5 × 10−4 s−1. Macroscopically, the stress–strain curve exhibited a steady increase in flow stress without a distinct peak stress. A constitutive relationship for Ti-55 alloy during high-temperature deformation was modified using the tensile experimental data to describe the steady-state flow stress and predict superplastic deformation. Furthermore, a processing map based on dynamic materials theory identified optimal conditions (940-950 °C, 5 × 10−4-1 × 10−3 s−1) for maximum power dissipation efficiency and m value. Microstructural analysis underscored the role of phase content and dynamic recovery in the optimal hot working region of Ti-55 alloy, highlighting the coexistence of α and β phases as a prerequisite for superplastic deformation.