Abstract: A novel low Young’s modulus Ti-Mo-Zr alloy was designed by first-principles calculation and high-throughput additive manufacturing (AM). Unlike the traditional approach of controlling β-phase stability in titanium alloy development, the designed Ti-16Mo-6Zr alloy, consisting of α′′ and β phases, exhibits a low Young's modulus (57.1 ± 3.4 GPa) and a high fracture strain (22.1 % ± 1.8 %). Serial samples with various compositions show that Young’s modulus can be reduced without loss of strength by adjusting the ratio of α′′/β phases reasonably. The mechanism by which the combination of metastable phases influences Young's modulus was elucidated through first-principles calculations of the Crystal Orbital Hamilton Population (COHP) and relevant integrated values. By controlling the amount of Mo atoms, a balance is achieved between Ti-Mo and Ti-Ti bonds withinα′′/β phases. The presence of Ti-Mo bonds induces localized lattice distortions, weakening the Ti-Ti bonds and reducing Young’s modulus. Meanwhile, Ti-Mo bonds are carefully regulated to avoid excessive rigidity in the material. This study has the potential to accelerate the development of Ti-Mo-based alloys, providing novel insights into controlling Young’s modulus by simultaneously regulating multiple metastable phases.

Key words: High-throughput additive manufacturing, Metastable phases, Young's modulus, First-principles calculation, Ti-Mo-Zr alloy