Effect of microstructure on the tensile strength of Ti6Al4V specimens manufactured using Additive Manufacturing Electron Beam Process

Electron beam melting additive manufacturing (AM) process has been developed for the manufacture of Ti6Al4V parts for the aerospace industry. In the AM research team from Airbus Group, this technology is being evaluated with a view to production of flight hardware. During the evaluation of the process, the microstructure variation as a function of geometry was studied. A distinctive microstructure was observed up to 0.5 mm from of part surface (the skin layer) and the thickness of the α-plate spacing varied depending on the thickness of the parts being produced. With the purpose of quantifying the influence of the grain thickness and the mechanical performance of the material, cylinders with nine different diameters (6 up to 40 mm diameter) were manufactured with 80 mm height. The microstructure characterisation showed how the α-plate spacing changed from thin to thick structures and the influence of grain size on tensile strength was quantified.