Constitutive analysis of the high-temperature deformation behavior of single phase a-Ti and α+β Ti-6Al-4V alloy

摘要

The high-temperature deformation behavior of the single-phase α (Ti-7.0Al-1.5V) and α + β (Ti-6Al-4V) alloy were determined and compared within the framework of self-consistent scheme at various temperature ranges. For this purpose, isothermal hot compression tests were conducted at temperatures between 650℃ ～ 950℃ to determine the effect of a/p phase volume fraction on average flow stress under hot-working condition. The flow behavior of a phase was estimated from the compression test results of single-phase a alloy whose chemical composition is close to that of a phase of Ti-6Al-4V alloy. On the other hand, the flow stress of β phase in Ti-6Al-4V was predicted by using self-consistent method. The flow stress of a phase was higher than that of p phase above 750℃, while the p phase revealed higher flow stress than α phase at 650℃. Also, at temperature above 750℃, the predicted strain rate of β phase was higher than that of α phase. It was found that the relative strength between α and β phase significantly varied with temperature.