In situ alloying of Ti10Mo fused tracks and layers via laser powder bed fusion

Abstract

Optimum process parameters for manufacturing a Ti10Mo alloy for biomedical applications via the laser powder bed fusion (LPBF) process were determined. Fused tracks were produced over a wide range of laser powers and scanning speeds, and layers were fused at varied hatch distances. The samples were analysed for continuity of the fused tracks, melting and distribution of the Mo powder particles in the Ti10Mo alloy layers, surface roughness, homogeneity of Mo in the alloy matrix and microhardness. The analysis revealed that the Mo powder particles melted completely in the alloy matrix with only pockets of Mo concentrations, mostly at the peripheries of the fused tracks due to the pushing effect. Complete melting of Mo in the Ti10Mo alloy matrix was due to the small size (1 μm) of the Mo powder particles used in the current experiment. The addition of Mo enhanced the wetting of the powder bed and prevented a pronounced balling effect. From this study, the parameter sets 150 W, 0.5 m/s and 200 W, 1.0 m/s both at a hatch distance of 80 μm, were obtained as the optimum process parameters. However, the Mo concentrations at the peripheries of the molten pool indicated that further research was required before a ‘completely’ homogenous sample could be manufactured via the LPBF process using elemental powder blends.