Improving strength and ductility of Ti-4Al-0.005B titanium alloy through tailoring equiaxed and lamellar microstructure during thermal mechanical process

The Ti-4Al-0.005B alloy were rolled at 940 degrees C or 990 degrees C followed by annealing at 650 degrees C. In order to control the final microstructure, rolling at medium temperature of 550 degrees C was processed in two other plates after rolling at 940 degrees C or 990 degrees C. The rolling and tensile behaviors of Ti-4Al-0.005B alloy with equiaxed and lamellar microstructure are comparatively studied using electron backscatter diffraction (EBSD) technique. It is found that the grain refinement mechanism of 940 degrees C and 940 + 550 degrees C rolled samples is continuous dynamic recrystallization (CDRX), while the 990 + 550 degrees C samples combine CDRX and twinning. The strong basal/near basal textures (B/N textures) in 940 degrees C and 940 + 550 degrees C rolled samples was mainly related to basal slip and pyramidal slip. Strong transverse textures (T-type texture) formed in 990 degrees C rolled sample due to variant selection during the beta ->alpha phase transformation and 990 + 550 degrees C rolled sample exhibits a mixed of T-type texture and B/N texture. The 990 + 550 degrees C rolled sample exhibited a best mechanical properties combined of strength and ductility due to its mixed texture and refined alpha grains. (C) 2022 The Author(s). Published by Elsevier B.V.

Automated summary

This study investigates the rolling and tensile behaviors of Ti-4Al-0.005B alloy using electron backscatter diffraction (EBSD) technique. The results show that different rolling and annealing processes significantly affect the grain refinement and texture formation of the alloy, with the 990 + 550 degrees C rolled sample exhibiting the best mechanical properties.