[T7] AM Sinter Based Technologies

[15A-T7-05] Successful Binder Jetting of Titanium Alloys Appeals to the Modification of Surface Oxides: A Plasma Treatment Approach

A. Simchi¹, *S. B. Hein¹, L. Reineke¹, R. Schlegel¹, M. Sandmann¹, A. Cogotti¹ (1.Fraunhofer Institute IFAM, Germany)

Keywords:Additive manufacturing, Powder processing, Titanium alloys, Surface treatment, Sintering

Metal binder jetting (MBJ) offers great opportunities for the fabrication of high-strength titanium alloys for aerospace applications as well as biomedical engineering. Herein, we present the effect of particle size and surface energy on the dynamics of binder spreading and imbibition in Ti6Al4V powder beds by employing high-speed camera imaging. It is shown that binder imbibition is significantly changed with the particle size due to geometrical-medicated wettability and capillary forces. To modify the surface energy of particles, a plasma technique is introduced. X-ray photoelectron spectroscopy shows that plasma treatment in nitrogen changes the type of surface oxide, thus enhancing the capillary rate by an order of magnitude and the theoretical binder saturation by about 50%. The beneficial effects of surface modification on the density, sinterability, and mechanical strength of TI6Al4V alloy are shown. Our results introduce a new strategy to enhance the processability of titanium powder for MBJ.