A new functional graded Ti–7.5Mo alloy prepared by in-situ laser solid forming

Laser solid forming (LSF), or direct laser deposition, is one kind of co-axial powder feeding laser additive manufacturing. It can fabricate near-net-shaped components with full density and fine microstructure. In this work, the almost dense Ti-7.5Mo alloy (over 99.5%) was manufactured by LSF from powder mixture of pure Ti and pure Mo. The as-fabricated sample presents a gradient microstructure along the building direction, which can be attributed to the thermal accumulation and in-situ heat treatment during LSF process. The gradient feature of mechanical properties was determined by tensile tests, in which the tensile sample is prepared in sheet form at several altitude position. As the deposited altitude increase, the yield strength and ultimate tensile strength decreases from 681 Pa and 791 MPa to 579 MPa and 686 MPa, respectively. In contrast, the elongation of as-deposited sample increases from 10% to 25 %. Compared with LSF processed commercial pure Ti and Ti-6Al-4V, it is worth to note that the Young¡¯s modulus of Ti-7.5Mo maintains at low value of 105 GPa for the entire sample. This work gives indication about a possible way to build complex shapes with strength and ductility graded Ti-Mo alloy for medical implant application.