Microtexture in additively manufactured Ti-6Al-4V fabricated using directed energy deposition

摘要

The additive manufacturing (AM) of α + β titanium alloys using electron beam (EB) and laser directed energy deposition (DED) processes has been widely characterized in both the as-deposited and post processed conditions. Fine basket weave α lath structures are commonly observed in both the as-deposited and post processed hot isostatically pressed (HIP) conditions for both laser and EB DED processes, but more in-depth knowledge of the crystallographic texturing and variant selection of the α laths growing from the primary β-grains across the height of EB DED Ti-6Al-4V structures is not well established. At locations near the substrate in both conditions, microtexturing is weak, but EB DED builds exhibit a strong microtexture and pronounced variant selection with increasing build height. On the other hand, the laser DED builds displayed weak texturing and no prominent variant selection across all heights. With the addition of HIP post processing, there was no change in microtexturing of the coarsened α laths for both the laser and EB structures, and the same variant selection observed in the as-deposited EB DED builds was present.