Load partition and microstructural evolution during in situ hot deformation of Ti-6Al-6V-2Sn alloys

Two Ti-6Al-6V-2Sn alloys, with globular and lamellar microstructures, are deformed at 750 °C during tensile and compression tests. The lamellar microstructure shows softening and higher peak stress values than the globular microstructure as a consequence of the Hall-Petch effect. In-situ high energy synchrotron diffraction experiments allow characterization of the load partition between α- and β-phases, plastic deformation mechanisms and texture evolution. The α-phase deforms mainly by rotation while the β-phase deforms by misorientation formation, acting merely as load transfer agent. The Taylor factor evolution of the α-phase and the annihilation of dislocations are analyzed qualitatively and quantitatively. The Taylor factor is connected to both the softening observed in the alloy with the lamellar microstructure and the texture development.