Effect of Metallic Y and CaF2 on Deoxidation and Inclusion Removal in an SHS-TiAl Alloy

In this study, the metallic Y, CaF2, and sponge Ti were employed to regulate the composition and achieve the deoxidation of the SHS-TiAl alloy, respectively. The results indicate that the metallic Y could effectively reduce the oxygen concentration of the SHS-TiAl alloys, which could all be controlled below 0.06 wt.%. The alloying control of SHS-TiAl could be further realized by adding sponge Ti with the achievement of a typical α + γ phase microstructure. Additionally, the CaF2 could adsorb the Y2O3 products, which were formed during the deoxidation reaction. However, due to the relatively high initial oxygen content in the SHS-TiAl alloy, the generated Y2O3 could not be fully removed, leading to the partial inclusions remaining in the alloy matrix. Also, the residual Y would react with Al in the alloy to form YAl2 inclusions.