Deoxidation of TiAl Alloy Scraps with Metallic Yttrium and Calcium Fluoride Slag

Abstract

Recently, the recycle of TiAl scrap becomes an important issue; however, its high oxygen content, which deteriorates mechanical properties, should be deoxidized. In this study, the scrap of TiAl alloy is melted using the water-cooling copper crucible, then the metallic yttrium and calcium fluoride slag are added on this melt. The deoxidation behavior of scrap is investigated, and the change of oxygen concentration is measured to evaluate the performance of this novel deoxidation technology. The results showed that the oxygen content of TiAl alloys under atmospheric pressure varied between 0.169 and 0.182 wt%. When the sample cell was vacuumed, the oxygen content varied between 0.131 and 0.167 wt%. In addition, the TiAl alloy contains a certain amount of element Y after deoxidation. This fact shows that the metallic yttrium and calcium fluoride slag exhibit a good deoxidation for the TiAl alloy melts. It may be one of the promising deoxidation processes of scrap of TiAl alloy.