Investigation of deformation behavior, microstructure evolution, and hot processing map of a new near-α Ti alloy

Abstract

Ti and its alloys are widely used in the aerospace, chemical equipment, and other fields due to their excellent comprehensive properties. Ti-0.3Mo-0.8Ni (TA10) alloy is a type of near-α Ti alloy with good corrosion resistance. The addition of Al element can improve the effect of solution strengthening in Ti alloy, thus, it can improve the strength of Ti alloy. The strength, corrosion resistance, and heat resistance can be further improved by the addition of Zr element. Therefore, a new Near-α Ti alloy (Ti-0.3Mo-0.8Ni-0.5Al-0.5Zr) was developed in the basis of TA10 alloy to enhance the mechanical properties of the alloy. In this study, the deformation mechanism and constitutive model of the new alloy were investigated. The results demonstrate that the extent of flow-softening phenomenon was obvious when deformed in the α+β phase field, and the extent was weakened when deformed in the single β phase field which exhibited a near steady-state flow. The primary mechanism of softening was DRX and DRV when deformed in the α+β phase field, and the DRV would be the main flow-softening mechanism when deformed in the single β phase field. The hot processing map was established based on Prasad's instability criterion, and the unsuitable processing parameters were 780–870 °C and 1-10 s−1.