Behavior and Mechanism of High-Temperature Stability between Tial-Based Alloy and Y(2)O(3)-Al(2)O(3) Composite Crucibles

In this work, Y(2)O(3) based composite crucibles with different Al(2)O(3) contents were designed and characterized. The stability behaviors and interaction mechanisms between molten Ti-47Al-2Cr-2Nb alloy and Y(2)O(3)-Al(2)O(3) composite crucibles were investigated at high temperature. Results showed that the surface morphology of crucibles and the degree of interfacial reactions between the composite crucibles and the metal melts varied with the change of Al(2)O(3) content in the crucible matrix. The pure Y(2)O(3) crucible was the densest and its chemical stability was the highest. With the increase in Al(2)O(3) content, the number of pores on the crucibles surface gradually increased and the interfacial reactions between the composite crucibles and the molten alloys became weaker. When the content of Al(2)O(3) in composite crucibles increased from 3.5 wt % to 10.5 wt %, the thickness of the interface layer of melt-crucible decreased from 150 µm to 50 µm, and the equilibrium contact angles between metal and crucibles gradually decreased from 69.3° to 64.2° at 1873 K.