Laser powder bed fusion parameters to produce high-density Ti-53%Nb alloy using irregularly shaped powder from hydride-dehydride (HDH) process

Abstract

Laser powder bed fusion (LPBF) – also known as selective laser melting (SLM) – is a technology of additive manufacturing (AM) that offers benefits to the fabrication of implants. This approach can create customized and complex parts with low elastic modulus to reduce stress shielding. The use of irregularly shaped powder is not common due to its low flowability and low apparent density. However, its low cost arouses interest in the production of materials by this technology. This work discloses the processing window that allows the fabrication of Ti-53wt.%Nb alloy parts with high density using irregularly shaped powder from hydride–dehydride (HDH) process and analyzes the influence of the process parameters on the microstructure and hardness of the samples manufactured by LPBF. Energy densities (EV) from 16 to 317 J/mm3 were investigated. Experimental density measurements by the Archimedes' principle and pore area fraction were calculated and relating to the density estimated based on X-ray diffraction (XRD) results of the HDH powder. Vickers hardness showed strong correlation to the content of interstitial elements of samples made under different EV. This work proves that is possible to obtain samples with high density using HDH powder in LPBF and that the content of interstitial elements increased with the energy density, as well as the hardness of the alloy.