Hot working of Ti–6Al–3Mo–2Zr–0.3Si alloy with lamellar α+β starting structure using processing map

Abstract

The hot deformation behavior of Ti–6Al–3Mo–2Zr–0.3Si alloy with lamellar α + β starting structure was characterized in the temperature range of 850–1050 °C and strain rate range of 0.001–1 s−1 by processing maps. The processing map in the α + β phase field exhibits a domain of dynamic recrystallization (DRX) with a peak efficiency of power dissipation of about 56% at 950 °C and 0.001 s−1, which is the optimum condition of lamellar globularization. In the β phase field, a lower strain rate domain with a representative power dissipation efficiency of about 48% represents β phase DRX. At higher strain rates above 0.5 s−1, flow instability occurs in the α + β phase field due to adiabatic shear bands and lamellar kinking, and the corresponding processing conditions are avoided. Finally, it is recommended that hot working of Ti–6Al–3Mo–2Zr–0.3Si alloy is best conducted in the β phase field at 1050 °C and 0.001 s−1, and in the α + β phase field at 950 °C and 0.001 s−1.