Microstructure Refinement Assisted by α-Recrystallization in a Peritectic TiAl Alloy

Abstract Fine-grained nearly-lamellar (FGNL) microstructures and ultrafine α2/γ lamellar microstructure were successfully obtained by means of α-recrystallization in a Ti-48Al-2Nb-2Cr alloy. The dynamic recrystallization of α phases and subsequent cooling control contributed to microstructure refinements, which were governed by small-strain α-deformation. Lamellar grain refinement is due to dominating continuous dynamic recrystallization (CDRX). Lamellar structure refinement is mainly achieved by the increase in γ lamellae precipitation sites by α-deformation and fast cooling. Finally, the microstructure evolution and control mechanisms were illustrated, suggesting a promising method for improving the mechanical properties of TiAl alloy.