The continual development of nickel-based superalloys has left them susceptible to the precipitation of topologically close-packed phases (TCPs), even during processing, producing blades for in-service use containing TCPs. This oral-poster presentation presents work done with BSE imaging and EDS to determine when these TCPs first precipitate. It demonstrates they occur in the earliest stages of the process, due to initial aluminum diffusion into the dendrite cores, promoting the formation of Ɣ’, in turn enriching the Ɣ channels with TCP forming elements, leading to the rapid precipitation of TCPs.