Microstructural study of Laser formed Ti-6Al-4V

A microstructural evaluation of as-deposited Lasformed(SM) Ti-6Al-4V, a Laser Additive Manufacturing (LAM) process, is the subject of the current work. Distinct features of the macrostructure include: large columnar prior-a grains (the initial solid to form upon cooling from the melt) have grown through multiple deposited layers due to epitaxial growth from previously solidified layers; a well defined heat affected zone; the presence of "layer bands," which are speculated to be a result of macrosegregation in the solidifying melt puddle and/or the complex thermal history that the part received as it was built, layer by layer. The microstructure of the layer band consists of larger colonies of acicular a outlined in transformed beta, whereas the adjacent material consists of smaller colonies having the same type of structure.