Abstract:

To investigate the influence of island scanning on the microstructures and mechanical properties of direct laser-deposited Ti-6Al-4V structures, two samples are prepared using island scanning and orthogonal successive scanning, respectively. The microstructures, relative density, and mechanical properties of the samples prepared using these two scanning strategies are compared. Each sample exhibits columnar β-grain morphology and basket-weave microstructure characterization. The grains of the sample prepared using island scanning are significantly finer than that prepared by orthogonal successive scanning due to faster cooling during deposition. However, the relative density of the sample prepared using island scanning was slightly smaller due to the concentration of lack-of-fusion pores at the overlap zone of the island. Tensile testing at room temperature indicates that the ultimate tensile strength and yield strength of the sample prepared using island scanning is enhanced due to finer grains, while the ductility of the sample is weakened due to defects.

Key words: Direct laser deposition, Ti-6Al-4V, Scanning strategies, Microstructure, Defects, Mechanical property