WEB Laser powder bed fusion of TiTa alloys: process optimisation and mechanical propertiesThursday (24.09.2020) 09:30 - 09:45 S: Structural Materials 1 Part of:
Additive manufacture (AM) is emerging as a viable manufacturing method for fabrication of a new type of β-titanium alloys. These alloys utilise β stabiliser such as Nb, Zr, Mo and Ta and are considered as promising next generation of biomedical titanium alloys with improved mechanical properties and biological response. However, the addition of refractory elements possess some processing challenges due to very high melting point of alloying elements.
In this work, fabrication of multiple compositions of TiTa alloys using laser powder bed fusion (L-PBF) is reported. Tantalum is selected as not only a favourable β stabiliser, but also due to its promising biocompatibility and promotion of osseointegration for use in the orthopaedics applications. The optimisation of processing parameters to produce fully dense samples with a minimised volume fraction of unmelted Ta particles is discussed focusing on different processing strategies. The morphology of the resulting microstructures was analysed with scanning electron microscopy (SEM) and phase identification supported with X-ray diffraction (XRD) analysis. The material was then assessed for mechanical properties under static and cyclic loading. The TiTa alloy showed similar strength to L-PBF titanium with half the elastic modulus and an altered microstructure caused by the ‘remelt’ scanning strategy. The alloy also demonstrated a superior yield stress normalised fatigue performance compared with commercially pure (CP) Ti, and Ti-6Al-4V ELI. The relationship between composition, microstructure and mechanical response of the TiTa alloy system will be elaborated.