Behavior and Mechanism of High-Temperature Stability between Tial-Based Alloy and Y2O3-Al2O3 Composite Crucibles

• Main Authors: Qingling Li, Huarui Zhang, Yongshuang Cui, Chunlei Yang, Ming Gao, Jinpeng Li, Hu Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2018-06-01
• Series: Materials
• Subjects: Y2O3; Al2O3; composite crucible; interface reaction; TiAl-based alloy; stability behavior
• Online Access: http://www.mdpi.com/1996-1944/11/7/1107

In this work, Y2O3 based composite crucibles with different Al2O3 contents were designed and characterized. The stability behaviors and interaction mechanisms between molten Ti-47Al-2Cr-2Nb alloy and Y2O3-Al2O3 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 Al2O3 content in the crucible matrix. The pure Y2O3 crucible was the densest and its chemical stability was the highest. With the increase in Al2O3 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 Al2O3 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.