Synthesis of Ti-5Al, Ti-6Al-7Nb, and Ti-22Al-25Nb alloys from elemental powders using powder-bed fusion additive manufacturing

A study has been undertaken to verify the feasibility of using powder-bed fusion additive manufacturing to fabricate Ti-5Al, Ti-6Al-7Nb, and Ti-22Al-25Nb alloys from elemental powders. Selective Laser Melting was used to produce bulk samples from mechanical mixtures of elemental powders for Ti-5Al, Ti-6Al-7Nb, and Ti-22Al-25Nb alloys. For Ti-Al-Nb system, annealing was carried out at 1050-1350 degrees C for 1 -3,5 h followed by furnace cooling. The systematic characterization of the samples was done using scanning electron microscopy (SEM), optical microscopy (OM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and tensile testing. It was shown that using elemental powders it is possible to synthesize titanium alloys by Selective Laser Melting. In case of Ti-5Al, powder-bed fusion of powders resulted in a homogeneous microstructure, while for Ti-6Al-7Nb and Ti-22Al-25Nb a subsequent heat treatment at 1350 degrees C temperature is required to fully dissolve niobium particles. (C) 2018 Elsevier B.V. All rights reserved.