Control of the homogeneity of the lamellar structure of a TiAl alloy refined by heat treatment

Recently, we reported a method for grain refinement of TiAl alloys by cyclic heat treatment (CHT) only. However, the final microstructure appeared inhomogeneous, containing grains of different sizes. In this study, a modified route is provided for grain refinement including a heat treatment step just below the α transus temperature. It is particularly shown that a coarse fully lamellar structure can be refined to a fine one with a size of ∼50 μm and the homogeneity of the microstructure can be significantly improved.