Novel nucleation mechanisms through satelliting in direct metal deposition of Ti-15Mo

Control of microstructural formation in direct metal deposition (DMD) presents a significant current limitation to the technology. Researchers have attempted to overcome this by thermal management in the process and through the formulation of new alloys. A novel material preparation method “satelliting” was used in combination with DMD to improve the microstructure of the deposited alloys. Three feedstocks of Ti-15Mo, including a satellited feedstock, a blend of Ti/Mo (150 μm) and blended Ti/Mo (3 μm), were prepared and used for DMD of Ti-15Mo. Fine equiaxed grains and near-equiaxed grains distributed uniformly were found in the deposited sample from satellited feedstock, while the samples from blended Ti/Mo (150 μm) and Ti/Mo (3 μm) are dominated by larger near-equiaxed grains and epitaxial columnar grains, respectively. The effect of the nucleation was verified by combinatory analysis of unmelted Mo particles. This demonstrates a new route to the manufacture of components through DMD which produces applicable microstructures directly from the build.