Preparation and Microstructure Properties of Low Oxygen High-purity Titanium Metal Foil

Low oxygen and high-purity titanium with thickness of 11 mm was used as raw material, which was obtained by electron beam melting (EBM). The metal foil with thickness of 30 μm was prepared by combined forming rolling technology. The surface morphology and microstructure of the metal foil were characterized by atomic force microscope (AFM), optical microscope (OM) and transmission electron microscope (TEM), and the mechanical properties such as yield strength, tensile strength and total elongation after fracture were studied. The results show that extreme extensibility phenomenon occurs in the cold rolling process, and the total elongation rate reaches 36 667%; the uniform thickness fluctuation of the metal foil is small, and the fluctuation ratio is 1.43%; the As-rolled microstructure forms ultrafine grains, which are mainly composed of equiaxed grains and elongated grains. The average grain size of equiaxed grains is less than 300 nm, and the width of elongated grains is about 50 nm to 250 nm. Most of the grains in the annealed microstructure become equiaxed grains with a size of about 15-20 µm. The metal foil has good plastic formability, with yield strength of 120 MPa, tensile strength of 250 MPa and total elongation after fracture of 10.1%. It is an ideal micro-forming raw material.