Evolution of the Microstructure of Laser Powder Bed Fusion Ti-6Al-4V During Post-Build Heat Treatment

The microstructure of additively manufactured Ti-6Al-4V (Ti64) produced by a laser powder bed fusion process was studied during post-build heat treatments between 1043 K (770 °C) and just above the β transus temperature 1241 (1008 in situ using high-energy X-ray diffraction. Parallel studies on traditionally wrought annealed Ti64 were completed as baseline comparison. initial final grain structures characterized electron backscatter Likewise, texture, dislocation density, texture determined with evolution microstructure, including phase evolution, internal stress, qualitative vanadium distribution constituent phases monitored as-built material single-phase hexagonal close packed (to measurement resolution) fine acicular structure exhibited high density intergranular residual stress. Recovery annealing stress observed to initiate concurrently at relatively low 770 (497 °C). Transformation initiated roughly 913 (640 °C), after recovery had occurred. These results are meant be used design resulting specified microstructures properties.