The Influence of Yttrium Content and Ceramic Crucible Materials on Desulfurization during Vacuum Induction Melting of DD5 Superalloys

In this study, the effect of adding different contents of yttrium (Y) during vacuum induction melting in Al₂O₃ and Y₂O₃ crucibles on the purification of DD5 alloys was investigated. The results show that the Y₂O₃ crucible exhibited great crucible stability and an excellent desulfurization effect when melting a Y-containing DD5 alloy. The S content of the alloy was reduced from 5.03 ppm to 1.36 ppm with the addition of 0.50 wt.% Y. Element Y combined with free S in the melt to form the YS phase, which was removed from the condensate shell and slag during the vacuum induction melting (VIM) process. Meanwhile, when the alloy was melted in the Y₂O₃ crucible with 0.50 wt.% Y addition, there was a reduction in S content from 2.77 ppm to 1.36 ppm compared to the Al₂O₃ crucible. Additionally, the loss of Y decreased from 0.12 wt.% to 0.05 wt.%.