Titanium Aluminide Alloys Melting in Al2O3 crucible, is coated by Y2O3
The melting process of gamma titanium aluminide alloy with composition Ti-44.4%Al-2.8%Nb-0.9%Mo (at. pct.) in yttria coated corundum crucible was investigated. The composition of the non-metallic inclusions, observed in the alloy microstructure, was determined by energy-dispersive X-ray analysis. Complex inclusions consist of aluminium and yttrium oxides were observed in the alloy. They are mainly located on the boundaries of the dendritic cells and have size from 1 to 5 microns. It was observed the inclusions of Ti 5Si 3 phase are also located on the boundaries of the dendritic cells. The results indicated that melting of titanium aluminide alloys in corundum crucible coated by yttria does not cause significant melt contamination unlike the melting in corundum and zirconia based crucibles.