A CoCrMo alloy conforming to the ASTM F75 standard was cast in an industrial environment and the microstructure of the metal carbides was studied. The CoCrMo alloy was characterized by a dendritic structure of a solid solution of chromium and molybdenum in cobalt with interdendritically precipitated carbides. Because of the high chromium content, the dominant phase was M23C6-type carbides, but chromium-rich carbides can be also of M7C3 and M3C2 types. The other elements in the alloy lead to M6C- and MC-type carbides. In the case of low carbon content, formation of metal carbides and intermetallic phases based on the alloying elements and cobalt is limited. The characterization of the samples was achieved by using optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), and energy dispersive spectroscopy (EDS) techniques for a better identification. In this study, the as-cast microstructure was a γ-Co (fcc) dendritic matrix, with precipitation of a secondary phase such as the M23C6 carbides at the grain boundaries and interdendritic zones

Keywords: CoCrMo alloy, ASTM F75, Metal carbides, γ-Co, M23C6, Microstructure