Design, preparation and properties of biomedical Ti–Nb quaternary alloys with high strength and low modulus: Insights from first-principles calculations

In this paper, we designed and developed biomedical β -type Ti–Nb quaternary alloy materials with high strength and low modulus. Building upon the d -electron alloy design method and the valence electron concentration e/a method, we use a Python program and thermodynamic theoretical parameters to determine a Ti–Nb quaternary alloy with the characteristics of a single-phase solid solution. Subsequently, we engage in theoretical and experimental investigations on the low modulus alloys identified through first-principles calculations. The results show that both Ti 7 Nb 6 Zr 1 Al 2 and Ti 11 Nb 2 Ta 2 Al 1 maintain a single β phase before and after cold rolling, which is related to the strong electronic density of states of s and p orbitals at low energy levels in the crystal structure of the two alloys. Ti 11 Nb 2 Ta 2 Al 1 has a strong charge distribution on the (001) crystal plane, which causes a large amount of internal stress under large deformation conditions to promote grain crushing and weaken the intensity of the (001)[1-10] texture in the ODF diagram of φ φ 2 = 45°. The cold-rolled Ti 11 Nb 2 Ta 2 Al 1 exhibits better corrosion resistance and biocompatibility than the cold-rolled Ti 7 Nb 6 Zr 1 Al 2 , and the good biocompatibility is related to the strong covalent bond between Al and Ta that inhibits the diffusion of Al ions. 90% cold-rolled Ti 11 Nb 2 Ta 2 Al 1 stands out as an exceptionally promising orthopedic implant material due to its high elastic allowable strain ( R eH /E), good corrosion resistance and biocompatibility.