Ti-6al-4v Adiabatic Shear Deformation Microstructure Evolution Mechanism Of The Thermal / Mechanical Parameters Of The Numerical Simulation Of The Shear Zone

The adiabatic shearing phenomena were often found in metallic materials under high-strain, high-strain-rate deformation.Ti and Ti alloy were applied widely in airline and aerospace industry because of its excellent performance.Ti is also sensitive to adiabatic shearing and easy to form adiabatic shear band (A SB).Now many research focus on the microstructural evolution mechanism in ASB.Based on the early works, the C program language and the least square method were used to obtain the thermal viscoplastic constitutive equation.A mechanical thermal coupled model was created and DEFORM-2D was used to analyze the thermal and mechanical parameters' changing during the process of adiabatic shearing.With the simulation result, the Ti alloy's dynamics of recrystallization were calculated and analyzed.The conclusions of this research indicated: The obtained constitutive equation based on Johnson-Cook model can accurately predict the flow stress.FE simulation result discovered the parameters distribution result which not only consisted with the experimental result but also predicted the unsteady point.According to the result of dynamics calculation, the adiabatic temperature rising was higher than 0.4Tm, but the duration time above 0.4Tm is very short and not enough for static recrystallization process.Traditional diffuse-controlled recrystallization mechanism can not account for the microstructural evolution in ASB.This indicated that diffuse is not the only controlled factor for recrystallization under high-strain-rate deformation.A mechanical assistant model can apply to account for the microstructural evolution in ASB, and the quantitative research on this model is the emphases of our future work.