| Abstract Scope |
The X-40 Co-based superalloy is widely used in the aerospace industry directly in as-cast condition, and its analysis in this condition is essential to understand further phase transformations during flight. With this in mind, this work focuses on analyzing the as-cast microstructure, phase transformation temperatures, and oxidation resistance. Observations and analyses were carried out via thermodynamic simulations, X-ray diffraction, scanning electron microscopy, scanning-transmission electron microscopy, energy-dispersive X-ray spectroscopy, dilatometry, and differential scanning calorimetry. The microstructure of the dendritic regions consisted of the α matrix, with MC, M7C3, and M23C6 carbides being present in the interdendritic spaces. It was found that precipitation of the Cr-rich carbides from the saturated α matrix may occur in the 650–750 °C range. It has been determined the incipient melting and liquidus temperatures of the X-40 alloy during heating are 1405 °C and 1421 °C, respectively.
The authors gratefully acknowledge the funding by National Centre for Research and Development, Poland, under grant POIR.01.01.01-00-0631/18. |