Suppression of texture and enhancement of high-temperature tensile property in heavily deformed gradient Ti2AlNb alloy

Abstract

Hot isostatic pressed Ti2AlNb alloys with trapezoid-shaped sections were hot rolled at 1000 °C to obtain the specimens with the gradient of deformation. The effect of the rolling reduction on the microstructure of the Ti2AlNb alloys was investigated by this high throughput method, and the mechanical properties of the gradient alloys were studied. With the increasing rolling reduction, the morphology of the orthorhombic (O) phase changed from well-arranged herringbone and palisade structures to a randomly distributed lamellar structure. By the electron backscatter diffraction characterization, the textures of the B2 and O phases changed with the increasing rolling reduction, and the texture of the O phase was depressed. The elevated-temperature tensile properties of the Ti2AlNb and Mo-modified Ti2AlNb gradient specimens were measured, and the deformation gradient was 36.0–43.0% and 43.0–50.0%, respectively. The heavily deformed gradient specimens exhibited higher strength and ductility than the lightly deformed ones, due to the increasing low-angle grain boundary and uniform distribution of local strain.

Keywords

• Ti2AlNb alloys
• Hot rolling
• Deformation gradient
• Texture
• Tensile properties