1. Microstructures of Ti-6Al-4V parts produced by additive manufacturing

1.1 Titanium and Ti-6Al-4V alloy metallurgy

With a density of 4.5, titanium belongs to the family of light metals like aluminum and magnesium. In addition to its low density, titanium has excellent corrosion resistance, thanks to the few nanometer layer of oxide on its surface. Titanium is also one of the few biocompatible metals, with excellent osseointegration properties, making it the metal of choice in the biomedical field. Pure titanium has a relatively low mechanical strength of around 450 MPa. However, the addition of alloying elements considerably improves its mechanical properties. Pure titanium exhibits an allotropic phase transformation at a temperature of 882°C where it changes from a hexagonal compact structure (hcp) (α phase) at low temperature, to a stable cubic centered...