A novel low-cost high-strength β titanium alloy: Microstructure evolution and mechanical behavior

A novel metastable beta-titanium alloy (Ti-4.8Al-5.6Mo-3 V-1.5Cr-1.6Fe) with low cost and high strength was designed using the D-electron theory approach. After solution treatment at 780 degrees C and aging at 470, 500, and 530 degrees C, a multiscale structure composed of beta matrix, primary alpha p (with a volume fraction of 21%), and precipitates alpha s were obtained. The density and average spacing of precipitates depended on the aging temperature. Dense alpha s with an average spacing (lambda) of less than 100 nm were precipitated during aging at 470 degrees C due to a greater driving force for the formation of alpha s. In contrast, coarse alpha s with an average spacing (lambda) greater than 100 nm were precipitated during aging at 530 degrees C due to a greater driving force for the growth of alpha s. The tensile properties were also sensitive to the density and spacing of precipitates alpha s inside the beta matrix. By controlling the density and average spacing of precipitates alpha s inside the beta matrix, a tensile strength ranging from 1512 MPa to 1648 MPa and tensile elongation ranging from 1.8% to 7.8% were achieved. Particularly, an excellent combination of high tensile strength (1512 MPa) and relatively high elongation (7.8%) was obtained by aging at 530 degrees C.(c) 2023 Elsevier B.V. All rights reserved.