Correlating spatial, temporal and chemical information in atom probe data: new insights from multiple evaporation in microalloyed steels

Multiple detector events (MDEs) in atom probe data, which are the result of simultaneous field evaporation of atomic species, have been investigated by correlating the temporal, chemical and spatial information from the raw detector data. We have applied this analysis to the investigation of microalloyed steels containing atomic clusters of Nb, C and N. As the degree of clustering increases, so does the tendency for simultaneous field evaporation of the clustered atoms. Although local magnification effects cause spatial distortions thereby lowering the spatial resolution of these ions specifically, strong correlations between their time of field evaporation and their chemistry are observed. Highlighting simultaneously field-evaporated atomic species is demonstrated to be a useful way to identify and visualize preferred solute–solute interactions. The time–chemical correlation introduced here is conceptually different to conventional spatial-chemical based analyses, but can also reflect changes in the atom...