Microstructures and mechanical properties of commercial titanium foils processed via the melt overflow process

Abstract

Microstructures, crystallographic textures, and mechanical properties have been investigated in commercial titanium alloy strips and foils processed via the melt overflow rapid solidification technology (MORST) technique. The direct cast (DC) foils were fully dense and exhibited equiaxed transformed grain structures and weak {112̄0}//normal direction solidification textures. After cold rolling, split {0002} textures were observed in both DC and ingot metallurgy (IM) processed foils with the basal poles concentrated approximately 30° from the normal direction towards the transverse direction. Crystallite orientation distribution function analysis indicated the presence of an orientation tube in the cast specimens near (1̄01 10)[12̄10] and (1̄018)[01̄10]. It is suggested that these textures are a result of the lattice rotations and nonuniform cooling that occur during the casting process. After rolling and annealing, main texture orientations were observed. The mechanical properties of the DC foils were comparable to IM foils. The results suggest that high quality titanium foils can be processed via MORST without the need for costly and wasteful hot rolling and annealing steps resulting in reduced processing costs.