Self-organizing nanostructured lamellar (Ti,Zr)C - A superhard mixed carbide

A nanoindentation and first-principles calculation study of a self-organizing nanostructured lamellar (Ti,Zr)C powder has been performed. The nanoindentation measurements reveal that the hardness of the carbide is comparable to the hardest transition metal carbides that have been reported previously. The origin of the super-high hardness is postulated to be due to the inherent bond strength and the large coherency strains that are generated when the carbide demixes within the miscibility gap. The high hardness is maintained at a high level even after 500 h aging treatment at 1300 °C. Therefore, it is believed that the new superhard mixed carbide has a high potential in various engineering applications such as in bulk cemented carbide and cermet cutting tools, and in surface coatings.