gamma-TiAl Fabricated by EBM as Innovative Material for Aerospace Applications with Low Environmental Impact

The purpose of this thesis is to investigate the material properties of gamma-TiAl (Ti-48Al-2Cr-2Nb) material manufactured by EBM for aerospace applications. Gas atomized Ti-48Al-2Cr-2Nb powders have been used as starting material in order to evaluate additive manufacturing for the production of near-net-shape gamma-TiAl parts to be employed in the field of aero-engines. In particular electron beam melting (EBM) is used to realize a selective densification of metal powder by melting it in a layerwise manner following a CAD model. The microstructure, the residual porosity and the chemical composition of the samples have been investigated both immediately after EBM and after heat treatments. High homogeneity of the samples, very low pickup of impurities (oxygen and nitrogen) with respect to the precursor powders have been observed and due to an extremely low level of internal defects, intrinsic to EBM process, the tensile properties of the EBM gamma-TiAl appear very consistent with a small scatter.