Abstract:
Y
2O
3 ceramics doped with different mass fraction (0-15%)of La
2O
3 were prepared by solid phase doping and vacuum sintering. The microstructure and flexural strength of the ceramics were studied. The melting test of TiAl alloy was carried out with the ceramic, and the interface microstructure, interface reaction type and oxygen content of alloy melt were analyzed. The results show that with increasing La
2O
3 doping content, the open porosity of La
2O
3-doped Y
2O
3 ceramics decreased first and then increased, and the flexural strength increased first and then decreased. When the mass fraction of La
2O
3 doping was 10%, the ceramics had the smallest open porosity of 0.45% and the highest flexural strength of 104 MPa. After melting TiAl alloy with 10wt% La
2O
3-doped Y
2O
3 ceramics, a transition layer with an average thickness of 2.10 μm appeared at the interface, and the phase of the transition layer was YLaO
3. A physical dissolution reaction occurred between ceramic and alloy. The oxygen mass fraction of alloy melt was 2 400 mg·kg
-1 and was only about 70% of that of ceramics without doping La
2O
3.