Site Specific Properties in Electron Beam Melted Ti-6Al-4V through Compositional Control

Additive manufacturing (AM) stands out from other manufacturing methods for the capability to produce multi-material parts using location-specific processing parameters (including scanning strategies) to allow the different materials to be positioned in desired regions or features of the geometry. Traditionally, multi-material AM builds are created from multiple feedstock materials, requiring multiple material feed systems, and often limiting compositional control to only one direction (build direction). Meanwhile, the high temperature processing of alloys (above melting temperatures), particularly in electron beam-based processes (which take place under vacuum), can lead to the vaporization of select elements present in the alloys. This work showcases samples wherein the vaporization of aluminum, in a Ti-6Al-4V alloy sample produced through electron beam melting with a single feedstock material, has been spatially controlled by varying process parameters. Modulating the aluminum vaporization that occurs during the AM process, composition variation within the plane perpendicular to the build direction (i.e., within a single layer) can be controlled. This compositional variation can be directly correlated to changes in microstructure and mechanical properties, both plastic and elastic. The result is a single sample in which both composition and material properties (microstructural, mechanical, etc.) have been spatially tailored by changing process parameters.