3D reconstruction and characterization of carbides in Ni-based high carbon alloy in a FIB-SEM system

Dual beam focused ion beam scanning electron microscopes (FIB-SEMs) are well suited for characterizing micron and submicron size microstructural features in three dimensions throughout a serial-sectioning experiment. In this article, a FIB-SEM instrument was used to collect morphological, crystallographic, and chemical information for an Ni–Ta–Al–Cr alloy of high carbon content. The alloy has been designed to have excellent tribological properties at elevated temperatures. The morphology, spatial distribution, scale, and degree of interconnection of primary carbides in the Ni–Ta–Al–Cr–C alloy was assessed via serial sectioning in a casting cross-section. The 3D reconstructions showed that the primary carbides and dendrites were forming a dendrite surrounded by primary carbide network over the entire cross-section. Additionally, the morphology and spatial distribution of secondary carbides after heat treatment was determined.