The invention discloses a design and preparation method of a double-phase
titanium alloy, and belongs to the field of
titanium alloy materials and
powder metallurgy. The double-phase
titanium alloy comprises the following components: less than or equal to 0.012% of C, less than or equal to 0.015% of H, less than or equal to 0.06% of N, 0.50-0.70% of O and the balance of Ti and inevitable impurities. According to the method, an HCP-FCC double-phase
titanium alloy forming part is obtained by utilizing high-
oxygen titanium alloy powder and combining with a
laser powder bed fusion (PBF-LB / M) technology for forming, wherein the
volume fraction of an FCC phase is gt; the density of the finally obtained double-phase
titanium alloy reaches 99.8% or above, the tensile strength is larger than or equal to 1100 MPa, the yield strength is larger than or equal to 1000 MPa, and the
ductility is larger than or equal to 20.0%. According to the double-phase titanium alloy, a certain amount of nano FCC phase is induced to be formed through interstitial
oxygen solid solution elements, the nano FCC phase and an HCP matrix have a coherent relationship, the Ti-O alloy can be effectively strengthened through the HCP-FCC double-phase structure, and the excellent
plasticity is kept. The double-phase titanium alloy is excellent in
mechanical property and does not depend on
solid solution strengthening, second-phase dispersion strengthening or
work hardening ways of expensive rare metals such as V, Mo and Nb, and green, low-carbon and low-cost preparation of the titanium alloy is facilitated.