Characterization of hot deformation behavior of a new near beta titanium alloy: Ti-7333

摘要

The hot deformation behavior of Ti-7333 titanium alloy in the temperature range of 770-970 ℃ and strain rate range of 10~(-3)-10 s~(-1) has been investigated by hot compressive testing on the Gleeble-3800 thermal and mechanical simulator. The results show that the maximum stress decreases with decreasing strain rate and increasing temperature. The flow curves characteristic under different deformation parameters show obvious different. And discontinuous yielding occurs to the alloy at a higher strain rate for all the experimental temperatures. The flow behaviors are described by the hyperbolic sine constitutive equation and the hot deformation activation energies in (α + β) and β region are calculated as 333.74 kJ/mol and 213.83 kJ/mol, respectively. By comparing with similar alloys such as Ti-5553 and Ti-1023, the new near β titanium alloy Ti-7333 exhibits weaker deformation resistance. Based on the dynamic materials model, the processing map is generated, which shows that there are three domains of peak efficiency. The highest peak efficiency of power dissipation of 65% occurs at about 855 ℃/ 0.001 s~(-1). Dynamic recovery and dynamic recrystallization occur during hot compression deformation and the degree of dynamic recrystallization is dependent sensitively on deformation temperature and strain rate. In the instability regimes, the material exhibits flow instabilities manifested in the form of flow localizations.