The use of inorganic process control agents to mill titanium‑niobium powders suitable for the selective laser melting process

Abstract

Alloying titanium (Ti) with niobium (Nb) offers the ability to develop a low-stiffness Ti alloy. The established methodologies for the fabrication of powders suitable for SLM processes are based on atomisation processes, which require high volume powder production to be financially viable. Consequently, these are unsuited for small batches used in bespoke alloys (e.g., Ti-Nb alloys). This work highlights the potential for milled powders as a cheaper feedstock for the SLM process. When following the established practice of using organic PCAs, this leads to the creation of interstitial phases during SLM fabrication. To alleviate that, this study puts forward the use of inorganic PCAs, such as tin (Sn) and calcium (Ca), to produce SLM-suitable powder. The use of inorganic PCAs, especially Ca, is effective, rendering the resultant powder with physical properties appropriate for the SLM process. These inorganic PCAs allow the fabrication of homogeneous Ti-Nb alloys with suitable hardness.