An Overview of Additive Manufacturing of Titanium Components by Directed Energy Deposition: Microstructure and Mechanical Properties

The directed energy deposition (DED) process can be employed to build net shape components or prototypes starting from powder or wires, through a layer-by-layer process. This process provides an opportunity to fabricate complex shaped and functionally graded parts that can be utilized in different engineering applications. DED uses a laser as a focused heat source to melt the in-situ delivered powder or wire-shaped raw materials. In the past years extensive studies on DED have shown that this process has great potential in order to be used for (i) rapid prototyping of metallic parts, (ii) fabrication of complex and customized parts, (iii) repairing/cladding valuable components which cannot be repaired by other traditional techniques. However, the industrial adoption of this process is still challenging owing to the lack of knowledge on the mechanical performances of the constructed components and also on the trustworthiness/durability of engineering parts produced by DED. This manuscript provides an overview of the additive manufacturing (AM) of titanium alloys and focuses in particular on the mechanical properties and microstructure of components fabricated by DED.