Evaluation of Yttria Applicability as a Crucible for Induction Melting of TiAl Alloy

In seeking cost reductions for precision cast parts made of TiAl alloy, application of induction melting using a ceramic crucible would be highly effective. Accordingly, consideration was given to the applicability of yttria as the material basis for such a ceramic crucible. Crucible specifications were first investigated, and a prototype crucible was fabricated with a suitable mixture ratio of raw materials from the standpoint of satisfactory thermal shock resistance and low reactivity with TiAl molten metal. As a result of induction melting testing of Ti-46 at%Al alloy, the developed crucible was found to facilitate substantially less contamination of the TiAl alloy, with lower oxygen concentration and hardness as compared with other conventional ceramic crucibles.