Investigation on interfacial reaction and wettability between 4777DS1 superalloy and ceramic core

Low reactivity and appropriate wettability between molten superalloys and ceramic materials are crucial for the production of high-quality superalloy castings. The sessile-drop experiment was employed to systematically investigate the interfacial reaction and wettability between the 4777DS1 superalloy and SiO2-based ceramic core at various temperatures (1,480 °C, 1,500 °C, 1,520 °C, and 1,550 °C). The wetting behavior and interfacial reaction products at different temperatures were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The interfacial reaction process and products were discussed, and the thermodynamic behavior and interfacial reaction mechanisms were elucidated. The results demonstrate that the wetting behavior and interfacial reaction between the 4777DS1 alloy and the ceramic core are significantly influenced by temperature. The wettability angle exhibits a trend of initial decrease followed by an increase with rising temperature, reaching a maximum of 139° at 1,480 °C, indicating poorer wettability of the 4777DS1 superalloy with the ceramic core and better casting properties at this specific temperature. The most intense interfacial reaction occurs at 1,520 °C, resulting in the formation of the main interfacial reaction products such as Al2O3, SiO2, and HfO2. Additionally, some crystal-like products rich in Si and Hf distribute on the reaction layer.