Effects of hot deformation parameters on lamellar microstructure evolution of Ti₂AlNb based alloy

The effects of deformation parameters, including deformation temperature, strain rate, and deformation degree, on the globularization behavior of lamellar structures of Ti₂AlNb based alloys with initial lamellar O were studied by isothermal compression in O+B2 filed through quantitative metallography. The results show that the phase composition and size are affected by the deformation temperature. In two-phase filed, the initial lamellar O transforms to B2 phase, and lamellar O becomes shorter and thicker with increasing the deformation temperature. The decrease of the strain rate is propitious to the diffusion of the microstructural composition, which improves the globularization of the initial lamellar O. Deformation degree exerts the greatest impact on the globularization of the lamellar O. The critical deformation degree is 0.3-0.5 and nearly all the lamellae are globularized when the deformation degree is 0.7.