Ni-based superalloy Alloy 625 is widely utilized in aerospace and supercritical water reactors due to its remarkable stability and high corrosion resistance. However, its low hardness and limited wear resistance render it unsuitable for demanding environments involving severe abrasion and hot corrosion, such as tip blade repairs. To address these limitations, metal matrix composites (MMCs) emerge as promising alternatives, offering superior mechanical and physical properties even under high-temperature conditions. Alloy 625-based MMC matrices can be developed by incorporating various ceramic particles to enhance their performance for refractory, abrasive, and structural applications. In this work, Alloy 625 with varying additions of xTiC particles (x = 1.25, 2.5, 3.75, 5.0 wt%) composites were prepared by arc casting. The microstructure and selected properties were analyzed using thermodynamic simulations, synchrotron radiation, light microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, hardness survey, tensile and stress rupture tests. It was observed that the ex-situ introduction of TiC particles into Alloy 625 strongly influenced its dendritic microstructure in the as-cast state. In the reference Alloy without TiC addition, Nb-rich carbides and Laves phase precipitates were found in the interdendritic spaces. During arc casting, TiC interacted with the melted Alloy 625, resulting in an increase in the amount of precipitates in the interdendritic spaces, including MC carbides and Laves phase. Mechanical testing at ambient and elevated temperature revealed that the addition of TiC particles significantly enhanced tensile strength and stress rupture resistance.

The authors gratefully acknowledge the funding by National Centre for Research and Development, Poland, under grant LIDER XIII – Development of the manufacturing and deposition technology of metal-ceramic nanocomposite coatings for the structural reconstruction of heat-resistant nickel-based superalloys (LIDER13/0036/2022).