Tensile properties of Ti-6Al-4V as-built by laser metal deposition: The relationship between heat affected zone bands, strain localization and anisotropy in ductility

ABSTR A C T Expanded structural applications of additively fabricated or repaired components rely on a thorough under-standing of relationships between the anisotropic microstructure and macroscopic mechanical properties. In the present study, Ti-6Al-4V as-built by laser metal deposition using a powder feedstock was investigated through an extensive characterization of microstructure, porosity and tensile properties along different loading directions. While no significant anisotropy in strength was noticed, the ductility was observed to vary significantly depending on the loading direction. Higher ductility along the build direction was found to result from strain delocalization using in-situ tensile tests combined with digital image correlation. Differences in mesoscale strain localization patterns stem from a specific distribution of alpha' plates in relation to HAZ bands. In addition, the influence of a variety of other features including the crystallographic textures, the 13 grain morphology, the distance to the free surface, the porosity and the argon shielding during manufacturing on tensile properties was also examined and discussed in light of existing literature.

Automated summary

In this study, the microstructure, porosity, and tensile properties of Ti-6Al-4V fabricated by laser metal deposition were characterized. It was found that while there was no significant anisotropy in strength, the ductility varied depending on the loading direction. An increase in ductility along the build direction was attributed to strain delocalization. Various factors such as crystallographic textures, grain morphology, distance to free surface, porosity, and shielding during manufacturing were also examined for their influence on the tensile properties.