Dynamic Recrystallization of β Phase of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si Alloy

Abstract:

An isothermal and constant strain rate compression test is carried out for the Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy with an equiaxed α+β microstructure in the temperature range of 1020~1080 ℃ and the strain rate range of 0.001~70 s-1. A power dissipation map is developed on the basis of flow stress data and by using the principles of dynamic material model. The results show that the steady state flow characteristics exist during hot compression deformation for the Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy in the temperature range 1020~1080 ℃. The dynamic recrystallization regime was identified in the power dissipation map and the microstructure examination was performed for validation. In the β phase field, the dynamic recrystallization occured in the temperature range of 1020~1080 ℃ and the strain rate range of 0.01~0.1 s-1 with the efficiency of power dissipation η mostly larger than 0.4, which is the optimum β forging processing parameters. It is proved that the power dissipation map based on dynamic material model is an effective method for successful β-forging and microstructure control