Laser-Directed Energy Deposition of Ti-Mo Biomaterials: Influencing Mechanisms of Molybdenum on Microstructure and Performance

Ti-Mo alloys with variable molybdenum (Mo) contents were fabricated by the laser-directed energy deposition process. The in-depth influencing mechanisms of the Mo element on microstructure and performance were quantitatively analyzed by experiment and first-principal calculation. Increasing Mo content decreased the formation and cohesive energies and stabilized the 𝛽 phase. The grain refining efficiency was increased, and the relative grain size was decreased by increasing the Mo content. The MS temperature decreased, and the acicular martensite formed with increasing Mo content. Both the solid-solution hardening and fine grain strengthening effects had positive influences, while the 𝛽 phase softening effect had a negative influence on the hardness and wear performance with increasing Mo content.