Direct oxygen removal from titanium aluminide scraps by yttrium reduction

Titanium aluminum (TiAl) scraps with a high oxygen content were treated with yttrium (Y) in a liquid chemical deoxidization process for recycling. The Gibbs free energy and the equilibrium constant of the deoxidization reaction were calculated, and the effects of the yttrium content and the system pressure on the oxygen content in the product were determined. The results showed that the oxygen in TiAl scraps could be removed by yttrium, and the oxygen content of the deoxidized TiAl scraps had only 10% of the original content after deoxidization. Furthermore, the oxygen content of the deoxidized TiAl scraps was decreased with the increase of yttrium addition. The higher the chamber pressure, the greater the oxygen content in the final TiAl alloys. These results were consistent with calculated values. The microstructure of the deoxidized alloys was akin to that of the original material; however, Y2O3 particles were observed in the deoxidized alloys.