Ultrafine duplex microstructure and excellent mechanical properties of TC4 alloy via a novel thermo-mechanical treatment

Combined with the decomposition of martensitic phase and the globularization of close-packed hexagonal α phase, TC4 alloy with ultrafine duplex microstructure and excellent mechanical properties is prepared by using a novel thermo-mechanical technique of plastic deformation and aging treatment. The dual phase of α and martensitic is obtained by quenching from α+β phase region. Then, the ultrafine equiaxial microstructure is come from the globularization of deformed α phase, and the ultrafine acicular microstructure forms by the decomposition of deformed martensitic phase during aging treatment. Compared with lath microstructure, equiaxial microstructure and coarse duplex microstructure, the ultrafine duplex microstructure of TC4 alloy possesses ultrahigh strength of 1350 MPa and good elongation of 11%.