低成本Ti-Al-V-Fe-O合金热变形行为及热加工图

Low cost Ti-6Al-2.5V-1.5Fe-0.15O titanium alloys were prepared by a consumable vacuum arc furnace. Thermal simulation experiments were carried out by Gleeble-1500D thermal simulator at different deformation temperatures (875~1100℃) and strain rates (0.001~1 s^-1) under 70% deformation. Then phase equations of two phase and single phase were established based on Arrhenius model, considering the influence of strain. The processing map was built by DMM and Prasad instability criterion. The results show that the alloy belongs to negative temperature and normal strain sensitivity material. The average thermal activation energy of two phase is 398.824 kJ/mol, which is bigger than that of the pure titanium, indicating the softening mechanism is related to the dynamic recrystallization. The average thermal activation energy of single phase is 210.93 kJ/mol, which id slightly higher than that of the pure titanium, and the softening is related to the dynamic recovery. Two flow instability zones appear on the processing map; the adiabatic shear easily occurs at moderate temperate (950~1070℃) and high strain rate (0.31~1 s^-1). The suitable zone for processing is the strain rate range of 0.001~0.01 s^-1 and temperature range of 875~925℃.