Microstructure, wear, and corrosion characterization of high TiC content Inconel 625 matrix composites

• Published in: Journal of materials research and technology 2019-01, Vol.8 (1), p.1102-1110
• Main Authors: Bakkar, Ashraf, Ahmed, Mohamed M.Z., Alsaleh, Naser A., Seleman, Mohamed M. El-Sayed, Ataya, Sabbah
• Format: Article
• Language: English
• Subjects: Corrosion; Hardness; Inconel 625; Microstructure; TiCp MMC; Wear
• ISSN: 2238-7854
• DOI: 10.1016/j.jmrt.2018.09.001

Titanium carbide/Inconel 625 (nickel alloy) metal matrix composites (MMCs) are developed for the combination of the super mechanical and corrosion properties of nickel alloy matrix and the high hardness of reinforcing titanium carbide particles (TiCp). The microstructure, hardness, wear, and corrosion behavior of MMCs with different volume contents of TiCp (25, 50 and 70vol.%) were investigated. The effect of increasing TiCp on the intermetallics and precipitates formed was examined using SEM/EDS and XRD analyses. The tribological behavior of the MMCs was investigated using wear testing with a pin-on-disk machine. The corrosion behavior was examined using potentiodynamic polarization experiments in 3% (w/v) NaCl solution. The results showed that the addition of TiCp into the Inconel 625 alloy resulted in formation of several intermetallics such as MoNi4, Cr2Ni3 and MoCr, in addition to molybdenum and chromium carbides in the matrix alloy. A great improvement in the hardness was resulted with addition of 25vol.% TiCp and consequently the wear resistance was also improved. Further increase of TiCp from 50 to 70vol.% did not result in more improvement of both hardness and wear resistance. The corrosion resistance of TiCp (25vol.%) composite was comparable to that of monolithic Inconel 625 matrix alloy, while clear reduction in the corrosion resistance was found in the 50 and 70vol.% composites.