Processing trials have produced a three-dimensional, thin-walled structure of representative aerospace component geometry, fabricated directly by laser melting of Ti6Al4V powder. This additive-built form has been subjected to metallographic characterization. The fabrication technique is evaluated as an economic, commercial process that can add features such as bosses or flanges as a hybrid-manufacturing route for existing forms of gas turbine components. The samples were extracted from six locations with different wall thickness, varying forms, and intersecting ligament geometries. A fine-scale Widmanstätten colony microstructure was consistent throughout the structure within grains elongated parallel to the axis of epitaxy. Evidence of limited grain boundary a was detected; however, this was never continuous around individual grains. A moderate Burgers texture was measured employing electron backscatter diffraction (EBSD), which is consistent with the melt/cast titanium alloy forms cooling through the β transus.
D. Clark, M.T. Whittaker, M.R. Bache
Metallurgical and Materials Transactions B, Vol 43B, April 2012, Pages 388-396 doi:10.1007/s11663-011-9599-x