Microstructure and crystallographic texture of pure titanium parts generated by laser additive manufacturing

In this paper, the microstructure and crystallographic texture of pure Ti thin walls generated by Additive Manufacturing based on Laser Cladding (AMLC) are analyzed in depth. From the results obtained, it is possible to better understand the AMLC process of pure titanium. The microstructure observed in the samples consists of large elongated columnar prior beta grains which have grown epitaxially from the substrate to the top, in parallel to the building direction. Within the prior beta grains, alpha-Ti lamellae and lamellar colonies are the result of cooling from above the beta-transus temperature. This transformation follows the Burgers relationship and the result is a basket-weave microstructure with a strong crystallographic texture. Finally, a thermal treatment is proposed to transform the microstructure of the as-deposited samples into an equiaxed microstructure of alpha-Ti grains.