Hot Deformation Behavior of Electron-Beam Cold-Hearth Melted Ti-6Al-4V Alloy

The deformation behavior and microstructure changes of electron-beam cold-hearth-melted (EBCHM) Ti-6Al-4V alloy were investigated. The stress-strain curves of the alloy were obtained, the constitutive model was established based on the Arrhenius equation, and the hot processing map was drawn. The results showed that the stress of the alloy decreases with increasing temperature and decreasing strain rate. In the beta phase field, there are more recrystallized grains when the strain rate is slow, and the recrystallization of the beta phase does not have enough time to occur when the strain rate is fast. There are obvious shear bands in the microstructure at the strain rate of 10 s-1. In the alpha + beta field, the morphology and crystallographic orientation of the microstructure changed simultaneously. Globularization is a typical microstructure evolution characteristic. The prismatic slip is easier to activate than basal and pyramidal slips. Moreover, globularization of the lamellar alpha phase is not synchronously crystallographic and morphological.