Effect of superheating on the structure and mechanical properties of Ti-46Al-8Nb alloy induction-melted in the fused BaZrO3 crucible

In this study, kilogram-level experiments for preparing the Ti-46Al-8Nb alloy were conducted using vacuum induction melting with a self-developed fused BaZrO₃ crucible. The effects of melting and casting temperatures (1560 °C, 1600 °C, and 1700 °C) on the alloy's oxygen content, structure, and mechanical properties were systematically investigated. The results showed that the alloy after melting at 1560 °C exhibited the lowest oxygen content (916 ppm), the smallest shrinkage cavities and cellular dendrites, along with the least amount of brittle α₂ phase. However, the formation of numerous microcracks within the alloy significantly deteriorated its mechanical properties. The alloy after melting at 1700 °C had the highest oxygen content (2941 ppm), the largest shrinkage cavities and dendrites, and the greatest amount of α₂ phase, all of which contributed to its poorest mechanical properties. In contrast, the alloy after melting at 1600 °C achieved a favorable balance among oxygen content (1169 ppm), microstructure, and phase composition, thereby exhibiting the best mechanical properties among the three alloys, with a tensile strength of 706 MPa and a fracture strain of 1.10 %.