Investigation of Thermal Deformation Behavior of TA15 Titanium Alloy Based on the Constitutive Model and 3D Processing Map
摘要
TA15 titanium alloy is widely used in load-bearing components and protective parts of aero-engines because of its high tensile strength, hardness and fatigue resistance, as well as high fracture toughness and ductility. In this paper, the hot compression experiment of TA15 alloy was carried out by means of Gleeble−3500 thermal simulator. The flow stress behavior of the alloy was characterized by the phenomenological constitutive model and the physical basic constitutive model, respectively, and both constitutive models considered the influence of strain. According to the energy dissipation coefficient and instability parameters, the 3D processing maps of Murty criterion were constructed. The results show that the average relative errors of the phenomenological and physical constitutive models are 7.8 % and 5.7 %, respectively, which have good prediction effects. Among them, the constitutive model with physical basis has better prediction effect. The experimental and processing maps indicate that the range of the flow instability zones of the TA15 alloy are roughly 700 ~ 760 °C and 0.05 ~ 1 s−1and 760 ~ 820 °C and 0.1 ~ 1 s−1, and the characteristics of the unstable structure are mechanical instability and local plastic flow. The alloy has high energy dissipation value at 700 ~ 760 °C and 0.001 ~ 0.05 s−1and 760 ~ 820 °C and 0.001 ~ 0.1 s−1, which is the area where relatively fine and uniform dynamic recrystallization microstructure is formed, and can be used as the best thermal processing parameter range.