Microstructural refinement of boron-containing β-solidifying γ-titanium aluminide alloys through heat treatments in the β phase field

► The microstructure can be refined by slow cooling from the β phase field. ► Rapid cooling results in much coarser microstructures. ► Borides act as inoculants for the α phase during the β/α transformation. ► Borides favour the precipitation of equiaxed and weakly textured α grains.